CMA Comerica Inc

DESCRIPTION OF THE SERIES A PREFERRED STOCK

The depositary will be the sole holder of the Series A Preferred Stock, as described under “Description of Depositary Shares” below, and all references in this prospectus supplement to the holders of the Series A Preferred Stock will mean the depositary. However, the holders of depositary shares will be entitled, through the depositary, to exercise the rights and preferences of the holder of the Series A Preferred Stock, as described under “Description of Depositary Shares.”

Under Comerica’s certificate of incorporation, the board of directors of Comerica is authorized to issue up to 10,000,000 shares of preferred stock in one or more series. Comerica’s board of directors is expressly authorized to provide for the issuance of shares of preferred stock in one or more series, with such voting powers, full or limited but not to exceed one vote per share, or without voting powers, and with such designations, preferences and relative, participating, optional or other special rights, and qualifications, limitations or restrictions thereof, as the board of directors may determine

The Series A Preferred Stock will be a single series of our authorized preferred stock. When issued, the Series A Preferred Stock will be fully paid and non-assessable. As of the date of this prospectus supplement, Comerica has no outstanding shares of preferred stock.

The Series A Preferred Stock will not be convertible into, or exchangeable for, shares of any other class or series of stock or other securities of Comerica. The Series A Preferred Stock will not have any maturity date and will not be subject to any sinking fund or other obligation of Comerica to redeem or repurchase the Series A Preferred Stock.

Shares of Series A Preferred Stock that are redeemed, purchased or otherwise acquired by us will be cancelled and will revert to authorized but unissued shares of preferred stock undesignated as to series.

Additional Shares of Series A Preferred Stock and Additional Depositary Shares

We may in the future from time to time, without notice to or consent of the holder of Series A Preferred Stock or the holders of the depositary shares, issue additional shares of the Series A Preferred Stock; provided, that any such additional shares of Series A Preferred Stock are not treated as “disqualified preferred stock” within the meaning of Section 1059(f)(2) of the Internal Revenue Code of 1986, as amended, and such additional shares are otherwise treated as fungible with the Series A Preferred Stock offered hereby for U.S. federal income tax purposes. The additional shares of Series A Preferred Stock would form a single series with the Series A Preferred Stock offered hereby. In the event that we issue additional Series A Preferred Stock after the date of initial issuance, dividends on such additional shares may accrue from the date of initial issuance or any other date we specify at the time such additional shares are issued. In the event we issue additional shares of Series A Preferred Stock, we will issue a corresponding number of additional depositary shares.

Ranking

Shares of the Series A Preferred Stock will rank:

As used in this prospectus supplement, “junior stock” means our common stock and any other class or series of stock of Comerica hereafter authorized over which the Series A Preferred Stock has preference or priority in the payment of dividends or in the distribution of assets on any liquidation, dissolution or winding up of Comerica.

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As used in this prospectus supplement, “parity stock” means any other class or series of stock of Comerica that ranks on parity with the Series A Preferred Stock in the payment of dividends and in the distribution of assets on any liquidation, dissolution or winding up of Comerica. As of the date of this prospectus supplement, there is no existing parity stock.

Dividends

Dividends on the Series A Preferred Stock will not be cumulative. If our board of directors or a duly authorized committee of our board of directors does not declare a dividend on the Series A Preferred Stock in respect of a dividend period, then no dividend will be deemed to have accrued for such dividend period, be payable on the applicable dividend payment date, or be cumulative, and we will have no obligation to pay any dividend for that dividend period to the holder of Series A Preferred Stock, including the holders of the depositary shares, and no related distribution will be made on the depositary shares, whether or not our board of directors or a duly authorized committee of our board of directors declares a dividend on the Series A Preferred Stock for any future dividend period.

The holder of Series A Preferred Stock will be entitled to receive, when, as, and if declared by our board of directors or a duly authorized committee of our board of directors, out of assets legally available for the payment of dividends under Delaware law, non-cumulative cash dividends based on the liquidation preference of the Series A Preferred Stock at a rate equal to:

In the event that we issue additional shares of Series A Preferred Stock after the original issue date, dividends on such shares may accrue from the original issue date or any other date we specify at the time such additional shares are issued.

If declared by our board of directors or a duly authorized committee of our board of directors, we will pay dividends on the Series A Preferred Stock, in arrears, quarterly on the 1^st day of January, April, July and October of each year, commencing on October 1, 2020, each such date, referred to as a “dividend payment date”.

If any date on which dividends would otherwise be payable is not a business day, then the dividend payment date will be the next business day without any adjustment to the amount of dividends paid. A “business day” means any day other than (i) a Saturday or Sunday or (ii) a day on which banking institutions in Dallas, Texas or New York, New York are authorized or obligated by law or executive order to close.

Dividends will be payable to holders of record of Series A Preferred Stock as they appear on our stock register at 5:00 p.m., New York City time, on the applicable record date, which will be the 15th calendar day before the applicable dividend payment date, or such other record date, not exceeding 30 days before the applicable dividend payment date, as will be fixed by our board of directors or a duly authorized committee of our board of directors. See “Description of Depositary Shares—Dividends and Other Distributions.”

A “reset date” means the First Reset Date and each date falling on the fifth anniversary of the preceding reset date. Reset dates, including the First Reset Date, will not be adjusted for business days. A “reset period” means the period from, and including, the First Reset Date to, but excluding, the next following reset date and thereafter each period from, and including, each reset date to, but excluding, the next following reset date. A “reset dividend determination date” means, in respect of any reset period, the day falling three business days prior to the beginning of such reset period.

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A “dividend period” is the period, from and including, a dividend payment date to, but excluding, the next dividend payment date, except that the initial dividend period will commence on, and include, the original issue date of the Series A Preferred Stock and will end on and exclude the October 1, 2020 dividend payment date.

Dividends payable on the Series A Preferred Stock for any dividend period will be computed on the basis of a 360-day year consisting of twelve 30-day months.

For any reset period commencing on or after the First Reset Date, the five-year treasury rate will be:

The five-year treasury rate will be determined by the calculation agent on the third business day immediately preceding the applicable reset date. If the five-year treasury rate for any dividend period cannot be determined pursuant to the methods described in the two bullet points above, the dividend rate for such dividend period will be the same as the dividend rate determined for the immediately preceding dividend period. Dividends on the Series A Preferred Stock will cease to accrue on the redemption date, if any, as described below under “—Redemption,” unless we default in the payment of the redemption price of the shares of the Series A Preferred Stock called for redemption.

We generally will be able to pay dividends and distributions upon liquidation, dissolution or winding up only out of assets legally available for such payment (after satisfaction of all claims for indebtedness and other non-equity claims). See “Description of Depositary Shares—Dividends and Other Distributions” for information about dividends on the depositary shares representing the Series A Preferred Stock.

Additionally, dividends on the Series A Preferred Stock will be subject to the satisfaction of conditions set forth in the capital adequacy guidelines or regulations of the Federal Reserve (or any successor bank regulatory authority that may become our applicable federal banking agency) applicable to dividends on the Series A Preferred Stock, if any.

Dividend Stopper

During each dividend period while the Series A Preferred Stock is outstanding, unless the full dividends for the immediately preceding dividend period on all outstanding shares of Series A Preferred Stock have been declared and paid or declared and a sum sufficient for the payment thereof has been set aside:

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When dividends are not paid in full on the shares of Series A Preferred Stock and any parity stock, all dividends declared on shares of Series A Preferred Stock and any parity stock will be declared on a proportional basis so that the amount of dividends declared per share will bear to each other the same ratio that accrued dividends for the then-current dividend period per share on Series A Preferred Stock, and accrued dividends, including any accumulations, on any parity stock, bear to each other.

Subject to the restrictions described above, dividends (payable in cash, stock or otherwise), as may be determined by our board of directors or a duly authorized committee of our board of directors, may be declared and paid on our common stock and any other stock ranking equally with or junior to the Series A Preferred Stock from time to time out of any assets legally available for such payment, and the holder of Series A Preferred Stock will not be entitled to participate in any such dividend.

Redemption

The Series A Preferred Stock will not be subject to any mandatory redemption, sinking fund or other similar provisions. Neither the holder of Series A Preferred Stock nor holders of depositary shares will have the right to require the redemption or repurchase of the Series A Preferred Stock.

Optional Redemption

We may redeem the Series A Preferred Stock at our option, in whole or in part, from time to time, during any par call period, at a redemption price equal to $100,000 per share (equivalent to $1,000 per depositary

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share), plus any declared and unpaid dividends, without accumulation of any undeclared dividends. In the event the applicable reset date that is the redemption date is not a business day, the redemption price will be paid on the next business day without any adjustment to the amount of the redemption price paid.

“Par call period” means the period from and including the July 1 of each year in which there is a reset date (which is three months prior to the reset date in such year) to and including such reset date.

Redemption Following a Regulatory Capital Treatment Event

We may redeem shares of the Series A Preferred Stock at any time within 90 days following a regulatory capital treatment event (defined below), in whole but not part, at a redemption price equal to $100,000 per share (equivalent to $1,000 per depositary share), plus any declared and unpaid dividends, without accumulation of any undeclared dividends.

A “regulatory capital treatment event” means the good faith determination by Comerica that, as a result of:

there is more than an insubstantial risk that Comerica will not be entitled to treat the full liquidation preference of the shares of Series A Preferred Stock then outstanding as “additional Tier 1 Capital” (or its equivalent) for purposes of the capital adequacy guidelines or regulations of the Federal Reserve (or any successor bank regulatory authority that may become our applicable federal banking agency), as then in effect and applicable, for as long as any share of Series A Preferred Stock is outstanding.

Redemption Procedures

If shares of the Series A Preferred Stock are to be redeemed pursuant to the terms described above under “—Optional Redemption” or “—Redemption Following a Regulatory Capital Treatment Event,” the notice of redemption will be given by first-class mail to the holder of record of the Series A Preferred Stock to be redeemed, mailed not less than 10 days nor more than 60 days prior to the date fixed for redemption thereof (provided that, if the holder of record is DTC, notice may be given in any manner permitted by DTC). Each notice of redemption will include a statement setting forth:

If notice of redemption of any shares of Series A Preferred Stock has been duly given and if the funds necessary for such redemption have been set aside by us for the benefit of the holders of any shares of Series A Preferred Stock so called for redemption, then, on and after the redemption date, dividends will cease to accrue on such shares of Series A Preferred Stock, such shares of Series A Preferred Stock will no longer be deemed

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outstanding and all rights of the holders of such shares will terminate, except the right to receive the redemption price, plus any declared and unpaid dividends, without accumulation of any undeclared dividends. See “Description of Depositary Shares—Redemption of Depositary Shares” for information about redemption of the depositary shares representing the Series A Preferred Stock.

In case of any redemption of only part of the shares of the Series A Preferred Stock at the time outstanding, the shares to be redeemed will be selected either pro rata or by lot or in such other manner as our board of directors (or a duly authorized committee of the board) may determine to be fair and equitable. Subject to the provisions hereof, our board of directors will have full power and authority to prescribe the terms and conditions upon which shares of Series A Preferred Stock will be redeemed from time to time.

Any redemption of the Series A Preferred Stock will be subject to our receipt of required prior approval by the Federal Reserve (or any successor bank regulatory authority that may become our applicable federal banking agency), if any, and to the satisfaction of conditions set forth in the capital adequacy guidelines or regulations of the Federal Reserve (or any successor bank regulatory authority that may become our applicable federal banking agency) applicable to redemption of the Series A Preferred Stock, if any.

Liquidation Rights

In the event we liquidate, dissolve or wind-up our business and affairs, either voluntarily or involuntarily, holders of the Series A Preferred Stock are entitled to receive a liquidation distribution of $100,000 per share (equivalent to $1,000 per depositary share), plus any declared and unpaid dividends, without accumulation of any undeclared dividends, before we make any distribution of assets to the holders of our common stock or any other class or series of stock ranking junior to the Series A Preferred Stock as to that distribution. The holder of the Series A Preferred Stock will not be entitled to any other amounts from us after it has received its full liquidation distribution.

In any such distribution, if the assets of Comerica are not sufficient to pay the liquidation distribution described above in full to the holder of the Series A Preferred Stock and all holders of any class or series of stock ranking on parity with the Series A Preferred Stock as to such distribution, the amounts paid to the holder of Series A Preferred Stock and all holders of such parity stock will be paid pro rata in accordance with the respective aggregate liquidation distribution owed to those holders. If the liquidation distribution described above has been paid in full to the holder of Series A Preferred Stock and the holders of such parity stock, the holders of any other class or series of stock ranking junior to the Series A Preferred Stock as to such distribution will be entitled to receive all remaining assets of Comerica according to their respective rights and preferences.

For purposes of this section, the sale, conveyance, exchange or transfer (for cash, shares of stock, securities or other consideration) of all or substantially all of the property and assets of Comerica will not be deemed a voluntary or involuntary dissolution, liquidation or winding up of the affairs of Comerica, nor will the merger, consolidation or any other business combination of any other corporation or person into or with Comerica be deemed to be a voluntary or involuntary dissolution, liquidation or winding up of the affairs of Comerica.

Because we are a holding company, our rights and the rights of our creditors and our stockholders, including the holder of the Series A Preferred Stock, to participate in the assets of any of our subsidiaries upon that subsidiary’s liquidation or recapitalization may be subject to the prior claims of that subsidiary’s creditors, except to the extent that we are a creditor with recognized claims against that subsidiary.

Voting Rights

The holder of the Series A Preferred Stock will have no voting rights, except as provided below or as required by law.

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Right to Elect Two Directors upon Nonpayment

Whenever dividends payable on the shares of Series A Preferred Stock have not been paid for six quarterly dividend periods, or their equivalent, whether or not consecutive, then the holder of the Series A Preferred Stock will have the right, with holders of any other equally ranked series of preferred stock that have similar voting rights and on which dividends likewise have not been paid (the “Voting Parity Securities”), voting together as a class, at a special meeting called at the request of the holders of at least 20% of the voting power of Series A Preferred Stock and any Voting Parity Securities (unless such request for a special meeting is received less than 90 calendar days before the date fixed for the next annual or special meeting of our stockholders, in which event such election will be held only at such next annual or special meeting of our stockholders) or at our next annual or special meeting of our stockholders, to elect two additional directors to our board of directors; provided, that the election of any such director does not cause us to violate the applicable corporate governance requirements of the exchange or trading market where our common stock is then listed or quoted, as the case may be. At any meeting held for the purpose of electing such directors, the presence in person or by proxy of the holders of shares representing at least a majority of the voting power of the Series A Preferred Stock and any Voting Parity Securities, voting together as a class, will be required to constitute a quorum of such shares. The affirmative vote of the holders of the Series A Preferred Stock and the holders of any Voting Parity Securities, voting together as a class, representing a majority of the voting power of such shares present at such meeting, in person or by proxy, will be sufficient to elect any such director.

Immediately prior to the election of any such directors, the number of directors that comprise our board of directors will be increased by two. Such voting rights and the term of the additional directors so elected will continue until continuous non-cumulative dividends for at least four consecutive quarterly dividend periods, or their equivalent will have been paid, or declared and set aside for payment, in full, on all outstanding shares of Series A Preferred Stock or the Voting Parity Securities entitled thereto. At that point, the right to elect additional directors terminates and the terms of office of the two additional directors so elected will terminate immediately, and the number of directors will be reduced by two and such voting rights of the holders of the Series A Preferred Stock and any Voting Parity Securities will cease, subject to any increase in the number of directors as described above due to the revesting of such voting rights in the event of each and every additional failure in the payment of dividends or six quarterly dividend periods, or their equivalent, whether or not consecutive, as described above.

The holder of Series A Preferred Stock, together with holders of any Voting Parity Securities, voting together as a class, may remove any director they elected. Any vacancy created by the removal of any such director may be filled only by the vote of the holders of the Series A Preferred Stock and any Voting Parity Securities, voting together as a class. If the office of either such director becomes vacant for any reason other than removal, the remaining director may choose a successor who will hold office for the unexpired term of the vacant office. In the event that both offices are vacant, the holder of Series A Preferred Stock and the holders of any Voting Parity Securities may, as set forth above, call a special meeting and elect such directors at such special meeting, or elect such directors at our next annual or special meeting of our stockholders.

The number of votes that each share of Series A Preferred Stock and any stock ranking equally with the Series A Preferred Stock participating in the votes described above will be in proportion to the liquidation preference of such share.

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Under regulations adopted by the Federal Reserve, if the holders of any series of preferred stock are or become entitled to vote for the election of directors, such series will be deemed a “class of voting securities” and a company holding 25% or more of the series, or 5% or more if it otherwise has the ability to exercise a “controlling influence” over us, may then be subject to regulation as a bank holding company in accordance with the Bank Holding Company Act of 1956, as amended. In addition, at the time the series is deemed a class of voting securities,

Other Voting Rights

So long as any shares of Series A Preferred Stock remain outstanding, the affirmative vote or consent of the holders of at least two-thirds of all outstanding shares of the Series A Preferred Stock voting separately as a class, will be required to:

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As used above under “Description of the Series A Preferred Stock—Voting Rights,” “senior stock” means any other class or series of stock of Comerica’s ranking senior to the Series A Preferred Stock with respect to payment of dividends or the distribution of assets upon liquidation, dissolution or winding up of Comerica. As of the date of this prospectus supplement, there is no existing senior stock.

The foregoing voting provisions will not apply if, at or prior to the time when the act with respect to which such vote would otherwise be required will be effected, all outstanding shares of Series A Preferred Stock will have been redeemed or called for redemption in accordance with the provisions described above upon proper notice and sufficient funds will have been set aside by us for the benefit of the holder of the Series A Preferred Stock to effect such redemption.

See “Description of Depositary Shares —Voting the Series A Preferred Stock” for information about voting of the depositary shares representing the Series A Preferred Stock.

Registrar

Computershare Trust Company, N.A. will be the transfer agent and registrar, Computershare Inc. will be the dividend disbursing agent, and Computershare Trust Company, N.A. and Computershare Inc. will jointly be the redemption agent for the Series A Preferred Stock.

Calculation Agent

We will appoint a calculation agent for the Series A Preferred Stock prior to the First Reset Date. We may appoint ourselves or an affiliate of ours as calculation agent.

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DESCRIPTION OF DEPOSITARY SHARES

In this prospectus supplement, references to “holders” of depositary shares mean those who own depositary shares registered in their own names, on the books that we or the depositary maintain for this purpose, and not indirect holders who own beneficial interests in depositary shares registered in street name or issued in book-entry form through DTC. Please review the special considerations that apply to indirect holders described in the “Book-Entry Issuance” section of this prospectus supplement.

This prospectus supplement summarizes specific terms and provisions of the depositary shares representing the Series A Preferred Stock and supersedes any conflicting description in the prospectus. As described above under “Description of the Series A Preferred Stock” and elsewhere in this prospectus supplement, we are issuing fractional interests in shares of the Series A Preferred Stock in the form of depositary shares. Each depositary share will represent a 1/100th ownership interest in a share of the Series A Preferred Stock, and will be evidenced by a depositary receipt. The shares of Series A Preferred Stock represented by depositary shares will be deposited under a deposit agreement among us, Computershare Inc., as joint depositary and Computershare Trust Company, N.A., as registrar and joint depositary, and the holders from time to time of the depositary receipts evidencing the depositary shares. Subject to the terms of the deposit agreement, each holder of a depositary share will be entitled, through the depositary, in proportion to the applicable fraction of a share of Series A Preferred Stock represented by such depositary share, to all the rights and preferences of the Series A Preferred Stock represented thereby (including dividend, redemption, liquidation and voting rights).

Immediately following the issuance of the Series A Preferred Stock, we will deposit the Series A Preferred Stock with the depositary, which will then issue the depositary shares to the underwriters. Copies of the forms of deposit agreement and the depositary receipt may be obtained from us upon request and in the manner described in the “Where You Can Find More Information” section of the accompanying prospectus.

Dividends and Other Distributions

The depositary will distribute any cash dividends or other cash distributions received in respect of the deposited Series A Preferred Stock to the record holders of depositary shares representing the Series A Preferred Stock represented thereby in proportion to the number of depositary shares held by the holders. The depositary will distribute any property received by it other than cash to the record holders of depositary shares entitled to those distributions, unless we determine that the distribution cannot be made proportionally among those holders or that it is not feasible to make a distribution (including any requirement that we or the depositary withhold an amount on account of taxes). In that event, we may adopt a method we deem equitable and practicable for purposes of effecting the distribution, including selling the property (at a public or private sale) and distributing the net proceeds from the sale to the holders of the depositary shares in proportion to the number of depositary shares they hold.

Record dates for the payment of dividends and other matters relating to the depositary shares will be the same as the corresponding record dates for the Series A Preferred Stock.

The amounts distributed to holders of depositary shares will be reduced by any amounts required to be withheld by the depositary or by us on account of taxes or other governmental charges.

Redemption of Depositary Shares

If we redeem the Series A Preferred Stock represented by the depositary shares, the depositary shares will be redeemed from the proceeds received by the depositary resulting from the redemption of the Series A Preferred Stock held by the depositary. The redemption price per depositary share will be equal to 1/100th of the redemption price per share payable with respect to the Series A Preferred Stock (or $1,000 per depositary share), plus any declared and unpaid dividends, without accumulation of any undeclared dividends. Whenever we redeem shares of Series A Preferred Stock held by the depositary, the depositary will redeem, as of the same redemption date, the number of depositary shares representing shares of Series A Preferred Stock so redeemed.

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In case of any redemption of less than all of the outstanding depositary shares, the depositary shares to be redeemed will be selected by the depositary pro rata or by lot or in such other manner as Comerica may determine to be fair and equitable. In any such case, the depositary will redeem depositary shares only in increments of 100 shares and any multiple thereof.

Liquidation Preference

In the event that we liquidate, dissolve or wind-up our business and affairs, either voluntarily or involuntarily, each holder of a depositary share will be entitled to receive a liquidation distribution of $1,000 per depositary share, plus any declared and unpaid dividends, without accumulation of any undeclared dividends, before we make any distribution of assets to the holders of our common stock or any other class or series of stock ranking junior to the Series A Preferred Stock as to that distribution.

Voting the Series A Preferred Stock

When the depositary receives notice of any meeting at which the holders of the Series A Preferred Stock are entitled to vote, the depositary will mail (or otherwise transmit by an authorized method) the information contained in the notice to the record holders of the depositary shares representing the Series A Preferred Stock. Each record holder of the depositary shares on the record date, which will be the same date as the record date for the Series A Preferred Stock, may instruct the depositary to vote the amount of the Series A Preferred Stock represented by the holder’s depositary shares. To the extent possible, the depositary will vote the amount of the Series A Preferred Stock represented by depositary shares in accordance with the instructions it receives provided, that the depositary receives such instructions sufficiently in advance of such voting to enable it to so vote or cause such Series A Preferred Stock to be voted. We will agree to take all reasonable actions that the depositary determines are necessary to enable the depositary to vote as instructed. If the depositary does not receive specific instructions from the holders of any depositary shares representing the Series A Preferred Stock, it will not vote (but, at its discretion, may appear at any meeting with respect to the Series A Preferred Stock unless directed to the contrary by the holders of all of the depositary shares) to the extent of the Series A Preferred Stock represented by the depositary shares.

Withdrawal of Preferred Stock

Unless the related depositary shares have previously been called for redemption, any holder of depositary shares may receive the number of whole shares of Series A Preferred Stock and any money and other property represented by such depositary receipts after surrendering the depositary receipts at the office of the depositary. Thereafter, without unreasonable delay, the depositary will deliver to such holder, or to the person or persons designated by such holder, the number of whole shares of Series A Preferred Stock and all money and other property, if any, represented by the depositary receipt or receipts so surrendered for withdrawal.

However, holders of such whole shares of Series A Preferred Stock will not be entitled to deposit such Series A Preferred Stock under the deposit agreement or to receive depositary receipts for such Series A Preferred Stock after such withdrawal. If the depositary shares surrendered by the holder in connection with such withdrawal exceed the number of depositary shares that represent the number of whole shares of Series A Preferred Stock to be withdrawn, the depositary will deliver to such holder at the same time a new depositary receipt evidencing such excess number of depositary shares. The depositary will not issue fractional shares of Series A Preferred Stock (or any cash payment in lieu thereof).

Amendment and Termination of the Deposit Agreement

The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may at any time be amended by agreement between us and the depositary. However, any amendment that materially and adversely alters the right of the holders of depositary shares will not be effective unless such amendment has been approved by the holders of depositary receipts representing in the aggregate at least a two-thirds majority of the depositary shares then outstanding. Every holder of an outstanding depositary receipt

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at the time any such amendment becomes effective, or any transferee of such holder, shall be deemed, by continuing to hold such depositary receipt, to consent and agree to such amendment and to be bound by the deposit agreement, that has been amended thereby.

The deposit agreement may be terminated by us or the depositary only if (i) all outstanding depositary shares issued thereunder have been redeemed pursuant to the deposit agreement, (ii) a final distribution in respect of the Series A Preferred Stock has been made in connection with any liquidation, dissolution or winding up of Comerica and such distribution has been distributed to the holders of the depositary receipts or (iii) upon consent of the holders of depositary shares representing in the aggregate not less than two-thirds of the depositary shares outstanding.

Charges of Preferred Stock Depositary; Taxes and Other Governmental Charges

We will promptly pay the depositary for all services rendered by the depositary under the deposit agreement (in accordance with a mutually agreed upon fee schedule) and will reimburse the depositary for its reasonable out-of-pocket expenses (including reasonable counsel fees and expenses) in connection with the services rendered by it under the deposit agreement. We will pay all charges of the depositary in connection with the initial deposit of the Series A Preferred Stock and the initial issuance of the depositary shares, all withdrawals of shares of Series A Preferred Stock by owners of depositary shares, and any redemption or exchange of the Series A Preferred Stock at our option. We will pay all transfer and other taxes and governmental charges arising solely from the existence of the depositary arrangements. All other transfer and other taxes and governmental charges will be at the expense of holders of depositary shares. If, at the request of a holder of depositary receipts, the depositary incurs charges or expenses for which we are not otherwise liable under the deposit agreement, such holder will be liable for such charges and expenses; provided, however, that the depositary may, at its sole option, require a holder of a depositary receipt to prepay the depositary any charge or expense the depositary has been asked to incur at the request of such holder of depositary receipts.

Resignation and Removal of Depositary

The depositary may resign at any time by delivering to us notice of its election to do so, such resignation to take effect upon the appointment of a successor depositary and its acceptance of such appointment but in no event later than 30 days after delivery of such written notice. We may at any time remove the depositary upon 30-day’s written notice of such removal. Such successor depositary must be appointed within 30 days after delivery of the notice of resignation or removal and must be a bank or trust company having its principal office in the United States and having a combined capital and surplus of at least $50,000,000 or an affiliate of any such bank or trust company.

Listing

We do not intend to apply for listing of the depositary shares on any securities exchange or for inclusion of the depositary shares in any automated dealer quotation system. We do not expect that there will be any separate public trading market for the shares of the Series A Preferred Stock except as represented by the depositary shares.

Form of Depositary Shares

The depositary shares will be issued in book-entry form through DTC, as described in “Book-Entry Issuance.” The Series A Preferred Stock will be issued in registered form to the depositary as described in “Description of the Series A Preferred Stock.”

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Miscellaneous

Upon our written instruction, the depositary will forward to holders of our depositary receipts any reports and communications from us that are received by the depositary with respect to the Series A Preferred Stock.

Neither we nor the depositary will be liable if we are prevented from or delayed in, by law or any circumstances beyond our control, performing our obligations under the deposit agreement. The depositary will not be subject to liability under the deposit agreement other than for its gross negligence, willful misconduct or bad faith and will not be liable for special, punitive, incidental, indirect or consequential losses or damages. The depositary will not be obligated to, but may, prosecute or defend any legal proceeding in respect of any depositary receipts, depositary shares or the Series A Preferred Stock represented by the depositary shares subject to the provision of indemnity satisfactory to the depositary. The depositary may rely on written advice of counsel or accountants, or information provided by persons presenting Series A Preferred Stock represented by the depositary shares for deposit, holders of depositary receipts or other persons, satisfactory to the depositary, to give such information, and on documents believed to be genuine and signed by a proper party.

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BOOK-ENTRY ISSUANCE

DTC will act as securities depositary for all of the depositary shares. We will issue the depositary shares only as fully-registered securities registered in the name of Cede & Co. (DTC’s nominee). We will issue and deposit with DTC one or more fully-registered global certificates for the depositary shares representing, in the aggregate, the total number of the depositary shares to be sold in this offering.

DTC has advised us that it is a limited purpose trust company organized under the New York Banking Law, a banking organization under the meaning of the New York Banking Law, a member of the Federal Reserve System, a clearing corporation under the meaning of the New York Uniform Commercial Code, and a clearing agency registered under the provisions of Section 17A of the Exchange Act. DTC holds securities that its participants deposit with DTC. DTC also facilitates the settlement among participants of securities transactions, like transfers and pledges, in deposited securities through electronic computerized book-entry changes in the participants’ accounts, eliminating in this manner the need for physical movement of securities certificates. Direct participants include securities brokers and dealers, banks, trust companies, clearing corporations and other organizations. DTC is owned by a number of its direct participants and by the New York Stock Exchange, Inc. and the Financial Industry Regulatory Authority, Inc. Others, like securities brokers and dealers, banks and trust companies that clear through or maintain custodial relationships with direct participants, either directly or indirectly, are indirect participants and also have access to the DTC system. The rules applicable to DTC and its participants are on file with the SEC.

Clearstream has advised us that it is incorporated under the laws of Luxembourg as a professional depositary. Clearstream holds securities for its participants and facilitates the clearance and settlement of securities transactions between its participants through electronic book-entry transfers between their accounts. Clearstream provides its participants with, among other things, services for safekeeping, administration, clearance and settlement of internationally traded securities and securities lending and borrowing. Clearstream interfaces with domestic securities markets in several countries through established depository and custodial relationships. As a professional depositary, Clearstream is subject to regulation by the Luxembourg Commission for the Supervision of the Financial Sector, also known as the Commission de Surveillance du Secteur Financier. Clearstream participants are recognized financial institutions around the world, including underwriters, securities brokers and dealers, banks, trust companies, clearing corporations and other organizations. Clearstream’s participants in the U.S. are limited to securities brokers and dealers and banks. Indirect access to Clearstream is also available to other institutions such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with Clearstream participants. Distributions with respect to interests in global securities held through Clearstream will be credited to cash accounts of its customers in accordance with its rules and procedures, to the extent received by the U.S. depositary for Clearstream.

Euroclear has advised us that it was created in 1968 to hold securities for its participants and to clear and settle transactions between Euroclear participants through simultaneous electronic book-entry delivery against payment, thereby eliminating the need for physical movement of certificates and any risk from lack of simultaneous transfers of securities and cash. Euroclear provides various other services, including securities lending and borrowing, and interfaces with domestic markets in several countries. Euroclear is operated by Euroclear Bank SA/NV under contract with Euroclear plc, a U.K. corporation. Euroclear participants include banks, including central banks, securities brokers and dealers and other professional financial intermediaries. Indirect access to Euroclear is also available to other firms that clear through or maintain a custodial relationship with a Euroclear participant, either directly or indirectly.

Purchases of depositary shares within the DTC system must be made by or through direct participants, who will receive a credit for the depositary shares on DTC’s records. The ownership interest of each actual purchaser of each depositary share is in turn to be recorded on the direct and indirect participants’ records. DTC will not send written confirmation to beneficial owners of their purchases, but beneficial owners are expected to receive written confirmations providing details of the transactions, as well as periodic statements of their holdings, from

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the direct or indirect participants through which the beneficial owners purchased depositary shares. Transfers of ownership interests in the depositary shares are to be accomplished by entries made on the books of participants acting on behalf of beneficial owners. Beneficial owners will not receive certificates representing their ownership interests in depositary shares, unless the book-entry system for the depositary shares is discontinued. Interests held through Clearstream and Euroclear will be recorded on DTC’s books as being held by the U.S. depositary for each of Clearstream and Euroclear, which U.S. depositaries will in turn hold interests on behalf of their participants’ customers’ securities accounts.

DTC has no knowledge of the actual beneficial owners of the depositary shares. DTC’s records reflect only the identity of the direct participants to whose accounts the depositary shares are credited, which may or may not be the beneficial owners. The participants will remain responsible for keeping account of their holdings on behalf of their customers.

Conveyance of notices and other communications by DTC to direct participants, by direct participants to indirect participants, and by direct participants and indirect participants to beneficial owners and the voting rights of direct participants, indirect participants and beneficial owners, subject to any statutory or regulatory requirements as is in effect from time to time, will be governed by arrangements among them.

We will send redemption notices to Cede & Co. as the registered holder of the depositary shares. If less than all of these depositary shares are redeemed, DTC’s current practice is to determine by lot the amount of the interest of each direct participant to be redeemed.

Although voting on the depositary shares is limited to the holders of record of the depositary shares, in those instances in which a vote is required, neither DTC nor Cede & Co. will itself consent or vote on depositary shares. Under its usual procedures, DTC would mail an omnibus proxy to us as soon as possible after the record date. The omnibus proxy assigns Cede & Co.’s consenting or voting rights to direct participants for whose accounts the depositary shares are credited on the record date (identified in a listing attached to the omnibus proxy).

We will make distribution payments on the depositary shares to DTC. DTC’s practice is to credit direct participants’ accounts on the relevant payment date in accordance with their respective holdings shown on DTC’s records unless DTC has reason to believe that it will not receive payments on the payment date. Standing instructions and customary practices will govern payments from participants to beneficial owners. Subject to any statutory or regulatory requirements, participants, and neither DTC nor we, will be responsible for the payment. We and any paying agent will be responsible for payment of distributions to DTC. Direct and indirect participants are responsible for the disbursement of the payments to the beneficial owners.

DTC may discontinue providing its services as securities depositary on any of the depositary shares at any time by giving reasonable notice to us. If a successor securities depositary is not obtained, final depositary shares certificates must be printed and delivered. We may at our option decide to discontinue the use of the system of book-entry transfers through DTC (or a successor depositary). After an event of default, the holders of a majority in number of depositary shares may discontinue the system of book-entry transfers through DTC. In this case, final certificates for the depositary shares will be printed and delivered.

We have obtained the information in this section about DTC and DTC’s book-entry system from sources that we believe to be accurate, but we assume no responsibility for the accuracy of the information. We have no responsibility for the performance by DTC or its participants of their respective obligations as described in this prospectus supplement or under the rules and procedures governing their respective operations.

“Beneficial owner” refers to the ownership interest of each actual purchaser of each depositary share.

“Direct participants” refers to securities brokers and dealers, banks, trust companies, clearing corporations and other organizations who, with the New York Stock Exchange, Inc. and the Financial Industry Regulatory

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Authority, Inc., own DTC. Purchases of depositary shares within the DTC system must be made by or through direct participants who will receive a credit for the depositary shares on DTC’s records.

“Indirect participants” refers to others, like securities brokers and dealers, banks and trust companies that clear through or maintain custodial relationships with direct participants, either directly or indirectly, and who also have access to the DTC system.

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DESCRIPTION OF DEBT SECURITIES

The following description of the debt securities sets forth the material terms and provisions of the debt securities. The debt securities offered by this prospectus will be unsecured obligations of Comerica and will be either senior or subordinated debt. The senior debt securities will be issued under an indenture (the “senior indenture”), between Comerica and The Bank of New York Mellon Trust Company, N.A., dated as of May 23, 2014, a copy of which is incorporated by reference as an exhibit to the Registration Statement of which this prospectus forms a part. The subordinated debt securities will be issued under an indenture (the “subordinated indenture”), between Comerica and The Bank of New York Mellon Trust Company, N.A., as successor trustee, dated as of May 1, 2003, a copy of which is incorporated by reference as an exhibit to the Registration Statement of which this prospectus forms a part. The senior indenture and the subordinated indenture are referred to in this prospectus collectively as the “indentures” and each individually as an “indenture.” The specific terms applicable to a particular issuance of debt securities and any variations from the terms set forth below will be set forth in the applicable prospectus supplement.

The following is a summary of the material terms and provisions of the indentures and the debt securities. You should refer to the indentures and the debt securities for complete information regarding the terms and provisions of the indentures and the debt securities. The indentures are substantially identical, except for the covenants of and provisions relating to subordination.

General

The indentures do not limit the aggregate principal amount of debt securities which Comerica may issue and provide that Comerica may issue debt securities under the indentures from time to time in one or more series. Comerica may from time to time, without giving notice to or seeking the consent of the holders of the debt securities of any series, issue debt securities having the same ranking and the same terms (other than the public offering price, issue date, payment of interest accruing prior to the issue date and, under some circumstances, the first interest payment date) as the debt securities of a previously issued series. Any additional debt securities having such identical terms, together with the debt securities of the applicable series previously issued, will constitute a single series of debt securities under the indenture. The indentures do not limit the amount of other indebtedness, or debt securities other than secured indebtedness, which Comerica or its subsidiaries may issue.

Unless otherwise provided in a prospectus supplement, the senior debt securities will be Comerica’s unsecured obligations and will rank equally with all of its other unsecured and unsubordinated indebtedness from time to time outstanding. The subordinated debt securities will be Comerica’s unsecured obligations and will be subordinated in right of payment to the prior payment in full of all of Comerica’s senior indebtedness, which term includes senior debt securities, as described below under “—Subordination.” In certain events of insolvency, the subordinated debt securities will also be subordinated to certain other financial obligations, as described below under “—Subordination.”

Because Comerica is a holding company, its rights and the rights of its creditors, including holders of debt securities, and shareholders to participate in any distribution of assets of any subsidiary upon the subsidiary’s liquidation or reorganization or otherwise would be subject to the prior claims of the subsidiary’s creditors, except to the extent that Comerica is a creditor of the subsidiary. The right of Comerica’s creditors, including holders of debt securities, to participate in the distribution of stock owned by Comerica in some of its subsidiaries, including its banking subsidiaries, may also be subject to approval by bank regulatory authorities having jurisdiction over these subsidiaries.

Each prospectus supplement will describe the following terms of the offered debt securities:

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Unless otherwise set forth in the applicable prospectus supplement, Comerica will only issue the debt securities in fully registered form without coupons.

Unless otherwise set forth in the applicable prospectus supplement, principal of, premium and interest on the debt securities will initially be payable at the corporate trust office of the trustee.

Interest on debt securities may be paid by check mailed to the persons entitled to the payments at their addresses appearing on the security register or by transfer to an account maintained by the payee with a bank located in the United States and will be payable on any interest payment date to the persons in whose names the debt securities are registered at the close of business on the regular record date with respect to the interest payment date.

Unless otherwise set forth in the applicable prospectus supplement, the trustee will act as the paying agent. Comerica may designate additional paying agents, rescind the designation of any paying agent or approve a change in the office through which any paying agent acts.

Unless otherwise set forth in the applicable prospectus supplement, holders may present the debt securities for transfer, duly endorsed or accompanied by a written instrument of transfer if so required by Comerica or the security registrar, or exchange for other debt securities of the same series containing identical terms and provisions, in any authorized denominations, and of a like aggregate principal amount, in each case at the office or agency maintained by Comerica for this purpose, which will initially be the corporate trust office of the trustee. Any transfer or exchange will be made without service charge, although Comerica may require payment of a sum sufficient to cover any tax or other governmental charge and any other expenses then payable. Comerica is not required to issue, register the transfer of, or exchange debt securities during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities and ending at the close of business on the day of mailing or register the transfer of or exchange any debt security selected for redemption, in whole or in part, except the unredeemed portion of any debt security being redeemed in part.

The debt securities may be issued as original issue discount securities, which means that they will bear no interest or bear interest at a rate which, at the time of issuance, is below market rates. Debt securities issued as original issue discount securities will be sold at a substantial discount below their principal amount. U.S. Federal income tax and other considerations applicable to original issue discount securities will be described in the applicable prospectus supplement.

If the purchase price, or the principal of, or any premium or interest on, any debt securities is payable in, or if any debt securities are denominated in, one or more foreign currencies or currency units, the restrictions, elections, U.S. Federal income tax considerations, specific terms and other information will be set forth in the applicable prospectus supplement.

Conversion and Exchange

The terms, if any, on which debt securities are convertible into or exchangeable for, either mandatorily or at Comerica’s or the holder’s option, property or cash, common stock, preferred stock or other securities, whether or not issued by Comerica, or a combination of any of these, will be set forth in the applicable prospectus supplement.

Global Securities

The debt securities may be issued, in whole or in part, in the form of one or more global securities that will be deposited with, or on behalf of, a depositary identified in the applicable prospectus supplement and registered in

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the name of the depositary or its nominee. Interests in any global debt security will be shown on, and transfers of the debt securities will be effected only through, records maintained by the depositary and its participants. The specific terms of the depositary arrangement will be described in the applicable prospectus supplement.

Subordination

Under the subordinated debt indenture, payment of the principal, interest and any premium on the subordinated debt securities will generally be subordinated and junior in right of payment to the prior payment in full of all Senior Indebtedness (as defined below). The subordinated debt indenture provides that no payment of principal, interest or any premium on the subordinated debt securities may be made unless we pay in full the principal, interest, any premium or any other amounts on any Senior Indebtedness then due. Also, no payment of principal, interest or any premium on the subordinated debt securities may be made if there shall have occurred and be continuing an event of default with respect to any Senior Indebtedness permitting the holders thereof to accelerate the maturity thereof, or if any judicial proceeding shall be pending with respect to any such default.

If there is any insolvency, bankruptcy, liquidation or other similar proceeding relating to Comerica, then all Senior Indebtedness must be paid in full before any payment may be made to any holders of subordinated debt securities. If after payment of the Senior Indebtedness there remains any amounts available for distribution and any person entitled to payment pursuant to the terms of Other Financial Obligations (as defined below) has not been paid in full all amounts due or to become due on the Other Financial Obligations, then these remaining amounts shall first be used to pay in full the Other Financial Obligations before any payment may be made to the holders of subordinated debt securities. Holders of subordinated debt securities must deliver any payments received by them to the trustee in bankruptcy or other person making payment or distribution of the assets of Comerica for application to the payment of all Senior Indebtedness and Other Financial Obligations remaining unpaid until all Senior Indebtedness and Other Financial Obligations are paid in full.

The subordinated debt indenture does not limit the amount of Senior Indebtedness and Other Financial Obligations that Comerica may incur. “Senior Indebtedness” means any of the following, whether incurred before or after the execution of the subordinated debt indenture:

but Senior Indebtedness does not include the subordinated debt securities or indebtedness that by its terms is subordinated to, or ranks on an equal basis with, the subordinated debt securities.

“Other Financial Obligations” means all obligations of Comerica to make payment pursuant to the terms of financial instruments, such as:

but Other Financial Obligations does not include Senior Indebtedness or indebtedness that by its terms is subordinated to, or ranks on an equal basis with, the subordinated debt securities.

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Events of Default, Waiver

An “Event of Default” with respect to a series of debt securities is defined in the indentures as:

With respect to the senior debt securities, if a default in the payment of principal, interest or other amounts payable on the senior debt securities, or in the performance of any covenant or agreement, or in a manner provided in the applicable supplemental indenture or form of security, with respect to one or more series of senior debt securities occurs and is continuing (other than a default arising out of certain events of bankruptcy or reorganization of Comerica), either the trustee or the holders of at least 25% in principal amount of the senior debt securities of such series then outstanding, treated as one class, may declare the principal of all outstanding senior debt securities of such series to be due and payable immediately. If a default arising out of certain events of bankruptcy or reorganization of Comerica occurs, the principal of all outstanding senior debt securities and any interest accrued thereon shall become due and payable immediately without any further action on the part of the trustee or the holders of the senior debt securities.

With respect to the subordinated debt securities, if a default arising out of certain events of bankruptcy or reorganization of Comerica occurs, either the trustee or the holders of at least 25% in principal amount of the subordinated debt securities of such series then outstanding, treated as one class, may declare the principal of all outstanding subordinated debt securities of such series to be due and payable immediately. The subordinated indenture does not provide for any right of acceleration of the payment of the principal of a series of subordinated debt securities upon a default in the payment of principal, premium, if any, or interest or a default in the performance of any covenant or agreement in the subordinated debt securities of that series or in the subordinated indenture. Accordingly, the trustee under the subordinated indenture and the holders will not be entitled to accelerate the maturity of those debt securities upon the occurrence of any of the events of default described above, except for those arising out of certain events of bankruptcy or reorganization of Comerica. If a default in the payment of principal, premium, if any, or interest or in the performance of any covenant or agreement in the subordinated debt securities of any series or in the subordinated indenture occurs, the trustee under the subordinated indenture may, subject to certain limitations and conditions, seek to enforce payment of such principal, premium, if any, or interest on the subordinated debt securities of that series, or the performance of such covenant or agreement.

In the case of original issue discount securities, only a specified portion of the principal amount may be accelerated.

Subject to certain conditions such declarations may be annulled and past defaults, except for uncured payment defaults on the debt securities, may be waived by the holders of a majority in principal amount of the outstanding debt securities of the series affected. An Event of Default with respect to one series of debt securities does not necessarily constitute an Event of Default with respect to any other series of debt securities. The indentures provide that the trustee may withhold notice to the holders of the debt securities of any default if the trustee considers it in the interest of the holders of the debt securities to do so. The trustee may not withhold notice of a default in the payment of principal of, interest on or any other amounts due under, such debt securities.

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The indentures provide that the holders of a majority in principal amount of outstanding debt securities of any series may direct the time, method, and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or other power conferred on the trustee. The trustee may decline to act if the direction is contrary to law and in certain other circumstances set forth in the applicable indenture. The trustee is not obligated to exercise any of its rights or powers under the applicable indenture at the request or direction of the holders of debt securities unless the holders offer the trustee indemnity satisfactory to it (in the case of the senior indenture) or reasonable indemnity (in the case of the subordinated indenture) against expenses and liabilities.

No holder of any debt security of any series has the right to institute any action for remedy unless such holder has previously given to the trustee written notice of default, the trustee has failed to take action for 60 days after the holders of not less than 25% in principal amount of the debt securities of such series make written request upon the trustee to institute such action and the holders offer the trustee indemnity reasonably satisfactory to it (in the case of the senior indenture) or reasonable indemnity (in the case of the subordinated indenture) against expenses and liabilities.

The indentures require Comerica to file annually with the trustee a written statement of no default, or specifying any default that exists.

Whenever the indentures provide for an action by, or the determination of any of the rights of, or any distribution to, holders of debt securities, in the absence of any provision to the contrary in the form of debt security, any amount in respect of any debt security denominated in a currency or currency unit other than U.S. dollars may be treated for any such action or distribution as the amount of U.S. dollars that could reasonably be exchanged for such non U.S. dollar amount. This amount will be calculated as of a date that Comerica specifies to the trustee or, if Comerica fails to specify a date, on a date that the trustee may determine.

Discharge, Defeasance and Covenant Defeasance

Discharge of Indenture. An indenture will cease to be of further effect with respect to debt securities of any series issued thereunder, except as to rights of registration of transfer and exchange, substitution of mutilated or defaced debt securities, rights of holders to receive principal, interest or other amounts payable under the debt securities, rights and immunities of the trustee and rights of holders with respect to property deposited pursuant to the following provisions and certain obligations of, and payments to, the trustee, if at any time:

The trustee, on demand of Comerica accompanied by an Officers’ Certificate and an Opinion of Counsel and at the cost and expense of Comerica, will execute proper instruments acknowledging such satisfaction of and discharging the Indenture with respect to such series.

Defeasance of a Series of Debt Securities at Any Time. Comerica may also discharge all of its obligations, other than as to rights of registration of transfer and exchange, substitution of mutilated or defaced debt securities, rights of holders to receive principal, interest or other amounts payable under the debt securities, rights and immunities of the trustee and rights of holders with respect to property deposited pursuant to the following provisions, under any series of debt securities at any time, which is referred to as “defeasance”.

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Comerica may be released with respect to any outstanding series of debt securities from the obligations to comply with certain restrictive covenants under the applicable indenture identified in the applicable prospectus supplement, and any omission to comply with such obligations will not constitute an event of default. Discharge under these procedures is called “covenant defeasance”.

Defeasance or covenant defeasance may be effected only if, among other things:

Modification of the Indenture; Waiver of Compliance

Each indenture contain provisions permitting Comerica and the trustee to modify the indenture or the rights of the holders of debt securities with the consent of the holders of not less than a majority in principal amount of each outstanding series of debt securities affected by the modification. Each holder of an affected debt security must consent to a modification that would:

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Each indenture also permits Comerica and the trustee to amend the indenture in certain circumstances without the consent of the holders of debt securities to evidence Comerica’s merger, the replacement of the trustee, to effect changes that do not affect any outstanding series of debt security, and for certain other purposes.

Consolidations, Mergers and Sales of Assets

Comerica may not merge or consolidate with any other corporation or sell or convey all or substantially all of its assets to any other corporation, unless either:

There are no covenants or other provisions in the indentures that would afford holders of debt securities additional protection in the event of a recapitalization transaction, a change of control of Comerica or a highly leveraged transaction. The merger covenant described above would only apply if the recapitalization transaction, change of control or highly leveraged transaction were structured to include a merger or consolidation of Comerica, or a sale or conveyance or lease of all or substantially all of its assets. However, Comerica may provide specific protections, such as a put right or increased interest, for particular debt securities, that Comerica would describe in the applicable prospectus supplement.

Governing Law

The indentures and debt securities will be governed by and construed in accordance with the laws of the State of New York.

The shares of common stock or preferred stock issuable upon exercise of the stock warrants will, when issued in accordance with the stock warrant agreement, be fully paid and non-assessable. This means that the shares will be paid for in full at the time they are issued, and, once they are paid for in full, there will be no further liability for further assessments or taxation.

Exercise of Stock Warrants

You may exercise your stock warrants by surrendering to the stock warrant agent your stock warrant certificate with the form of election to purchase on the reverse of the certificate properly completed and executed by you, or your authorized agent, which signature must be guaranteed by a bank or trust company, by a broker or dealer which is a member of the Financial Industry Regulatory Authority, Inc. (“FINRA”) or by a member of a national securities exchange. You must indicate on the form of election whether you are electing to exercise all or a portion of the stock warrants evidenced by the certificate. You must also submit a payment of the aggregate exercise price of the stock warrants to be exercised in lawful money of the United States along with your stock warrant certificates, unless otherwise set forth in the applicable prospectus supplement. Upon receipt of the stock warrant certificate, form of election and aggregate payment, if applicable, by the stock warrant agent, the stock warrant agent will requisition from the transfer agent for the common stocks or the preferred stocks, as the case may be, a certificate representing the number of common stocks or preferred stocks purchased for issuance and delivery to you or upon your written order. If you exercise less than all of the stock warrants evidenced by any stock warrant certificate, the stock warrant agent shall deliver to you a new stock warrant certificate representing your unexercised stock warrants.

Anti-Dilution and Other Provisions

The exercise price payable, the number of shares of common stock or preferred stock purchasable upon the exercise of each stock warrant, and the number of stock warrants outstanding are subject to adjustment if specified events occur. These events include:

In lieu of adjusting the number of shares of common stock or preferred stock purchasable upon exercise of each stock warrant, Comerica may elect to adjust the number of stock warrants. No adjustment in the number of shares purchasable upon exercise of the stock warrants will be required until cumulative adjustments require an adjustment of at least 1% in the number of shares purchasable. Comerica may also, at its option, reduce the exercise price at any time. No fractional shares will be issued upon exercise of stock warrants, but Comerica will pay the cash value of any fractional shares otherwise issuable. Notwithstanding the preceding sentences, in case of any consolidation, merger, or sale or conveyance of Comerica’s property, Comerica in its entirety or

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substantially in its entirety, you, as a stock warrant holder, shall have the right to the kind and amount of shares of stock and other securities and property, including cash, receivable by a holder of the number of common stocks or preferred stocks into which your stock warrants were exercisable immediately prior to this event.

No Rights as Shareholders

You will not be entitled, by virtue of being a stock warrant holder, to vote, to consent, to receive dividends, to receive notice as shareholders with respect to any meeting of shareholders for the election of Comerica’s directors or any other matter, or to exercise any rights whatsoever as shareholders of Comerica.

Exercise of Debt Warrants

You may exercise your debt warrants by surrendering at the office of the debt warrant agent your debt warrant certificate with the form of election to purchase on the reverse side of the certificate properly completed and signed by you, which signature must be guaranteed by a bank or trust company, by a broker or dealer which is a member of FINRA or by a member of a national securities exchange. You must also submit a payment in full of the exercise price, as set forth in the applicable prospectus supplement. Upon the exercise of debt warrants, Comerica will issue the debt securities in authorized denominations in accordance with your instructions. If you exercise less than all of the debt warrants evidenced by your debt warrant certificate, a new debt warrant certificate will be issued for the remaining number of debt warrants.

Any initial public offering prices, discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time.

If underwriters are used in an offering of offered securities, such offered securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. The securities may be offered either to the public through underwriting syndicates represented by one or more managing underwriters or by one or more underwriters without a syndicate. Unless otherwise specified in connection with a particular offering of securities, the underwriters will not be obligated to purchase offered securities unless specified conditions are satisfied, and if the underwriters do purchase any offered securities, they will purchase all offered securities.

In connection with underwritten offerings of the offered securities and in accordance with applicable law and industry practice, underwriters may over-allot or effect transactions that stabilize, maintain or otherwise affect the market price of the offered securities at levels above those that might otherwise prevail in the open market, including by entering stabilizing bids, effecting syndicate covering transactions or imposing penalty bids, each of which is described below.

These transactions may be effected on the NYSE, in the over-the-counter market, or otherwise. Underwriters are not required to engage in any of these activities, or to continue such activities if commenced.

If dealers are utilized in the sale of offered securities, Comerica will sell such offered securities to the dealers as principals. The dealers may then resell such offered securities to the public at varying prices to be determined by such dealers at the time of resale. The names of the dealers and the terms of the transaction will be set forth in the prospectus supplement relating to that transaction.

Offered securities may be sold directly by Comerica to one or more institutional purchasers, or through agents designated by Comerica from time to time, at a fixed price or prices, which may be changed, or at varying prices determined at the time of sale. Any agent involved in the offer or sale of the offered securities in respect of which this prospectus is delivered will be named, and any commissions payable by Comerica to such agent will be set forth, in the prospectus supplement relating to that offering. Unless otherwise specified in connection with a particular offering of securities, any such agent will be acting on a best efforts basis for the period of its appointment.

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As one of the means of direct issuance of offered securities, Comerica may utilize the services of an entity through which it may conduct an electronic “dutch auction” or similar offering of the offered securities among potential purchasers who are eligible to participate in the auction or offering of such offered securities, if so described in the applicable prospectus supplement.

If so indicated in the applicable prospectus supplement, Comerica will authorize agents, underwriters or dealers to solicit offers from certain types of institutions to purchase offered securities from Comerica at the public offering price set forth in such prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. Such contracts will be subject only to those conditions set forth in the prospectus supplement and the prospectus supplement will set forth the commission payable for solicitation of such contracts.

Comerica Securities, Inc., Comerica’s broker-dealer subsidiary, is a member of FINRA, and may participate in distributions of the offered securities. Accordingly, offerings of offered securities in which Comerica Securities, Inc. participates will conform with the requirements of FINRA’s conflict of interest rules.

This prospectus, together with any applicable prospectus supplement, may also be used by any broker-dealer subsidiary of Comerica in connection with offers and sales of the offered securities in market-making transactions, including block positioning and block trades, at negotiated prices related to prevailing market prices at the time of sale. Any of Comerica’s broker-dealer subsidiaries may act as principal or agent in such transactions. None of Comerica’s broker-dealer subsidiaries have any obligation to make a market in any of the offered securities and may discontinue any market-making activities at any time without notice, at its sole discretion.

One or more dealers, referred to as “remarketing firms,” may also offer or sell the securities, if the prospectus supplement so indicates, in connection with a remarketing arrangement contemplated by the terms of the securities. Remarketing firms will act as principals for their own accounts or as agents. The prospectus supplement will identify any remarketing firm and the terms of its agreement, if any, with Comerica and will describe the remarketing firm’s compensation. Remarketing firms may be deemed to be underwriters in connection with the remarketing of the securities.

Underwriters, dealers and agents may be entitled, under agreements with Comerica, to indemnification by Comerica relating to material misstatements and omissions. Underwriters, dealers and agents may be customers of, engage in transactions with, or perform services for, Comerica and affiliates of Comerica in the ordinary course of business.

Except for securities issued upon a reopening of a previous series, each series of offered securities will be a new issue of securities and will have no established trading market. Any underwriters to whom offered securities are sold for public offering and sale may make a market in such offered securities, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice. The offered securities may or may not be listed on a securities exchange. No assurance can be given that there will be a market for the offered securities.

ERISA CONSIDERATIONS

A fiduciary of a pension, profit-sharing or other employee benefit plan governed by the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), should consider the fiduciary standards of ERISA in the context of the ERISA plan’s particular circumstances before authorizing an investment in the offered securities of Comerica. Among other factors, the fiduciary should consider whether such an investment is in accordance with the documents governing the ERISA plan and whether the investment is appropriate for the ERISA plan in view of its overall investment policy and diversification of its portfolio.

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Certain provisions of ERISA and the Internal Revenue Code of 1986, as amended (the “Code”), prohibit employee benefit plans (as defined in Section 3(3) of ERISA) that are subject to Title I of ERISA, plans described in Section 4975(e)(1) of the Code (including, without limitation, individual retirement accounts and Keogh Plans) that are subject to Section 4975 of the Code, and entities whose assets include plan assets by reason of a plan’s investment in such entities (including, without limitation, as applicable, insurance company general accounts), from engaging in certain transactions involving “plan assets” with parties that are “parties in interest” under ERISA or “disqualified persons” under the Code with respect to the plan or entity. Governmental and other plans that are not subject to ERISA or to the Code may be subject to similar restrictions under non-U.S., state, federal or local law. Any employee benefit plan or other entity, to which such provisions of ERISA, the Code or similar law apply, proposing to acquire the offered securities should consult with its legal counsel.

Comerica has subsidiaries, including insurance company subsidiaries and broker-dealer subsidiaries, that provide services to many employee benefit plans. Comerica and any such direct or indirect subsidiary of Comerica may each be considered a “party in interest” and a “disqualified person” to a large number of plans. The acquisition of offered securities of Comerica by any such plan would be likely to result in a prohibited transaction between the plan and Comerica.

Accordingly, unless otherwise provided in connection with a particular offering of securities, offered securities may not be acquired, held or disposed of by any plan or any other person investing “plan assets” of any plan that is subject to the prohibited transaction rules of ERISA or Section 4975 of the Code or other similar law, unless one of the following Prohibited Transaction Class Exemptions (“PTCE”) or a similar exemption or exception applies to such acquisition, holding and disposition:

Unless otherwise provided in connection with a particular offering of securities, any purchaser or transferee of the offered securities or any interest therein will be deemed to have represented and warranted to Comerica on each day including the date of its acquisition of the offered securities through and including the date of disposition of such offered securities that either:

Due to the complexity of these rules and the penalties imposed upon persons involved in prohibited transactions, it is important that any person considering the acquisition of the offered securities with plan assets consult with its counsel regarding the consequences under ERISA and the Code, or other similar law, of the acquisition and ownership of offered securities and the availability of exemptive relief under the class exemptions listed above.

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The sale of any securities to any plan is in no respect a representation by Comerica or any of its affiliates or representatives that such an investment is appropriate for or meets all relevant legal requirements with respect to investments by plans generally or any particular plan. Please consult the applicable prospectus supplement for further information with respect to a particular offering and, in certain cases, further restrictions on the purchase or transfer of securities.

LEGAL MATTERS

The validity of these securities has been passed upon for Comerica by Mayer Brown LLP, Chicago, Illinois. In connection with particular offerings of the securities in the future, the validity of the securities may be passed upon for Comerica by one of Comerica’s lawyers or other counsel to Comerica named in the applicable prospectus supplement and for underwriters, agents or dealers by Mayer Brown LLP, Chicago, Illinois. From time to time, Mayer Brown LLP has represented Comerica on various matters and may do so in the future.

EXPERTS

The consolidated financial statements of Comerica Incorporated incorporated by reference in Comerica Incorporated’s Annual Report (Form 10-K) for the year ended December 31, 2017, and the effectiveness of Comerica Incorporated’s internal control over financial reporting as of December 31, 2017 have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, incorporated by reference therein, and incorporated herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

Comerica files annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any document Comerica files in the SEC’s Public Reference Room, 100 F Street, N.E., Washington, D.C. 20549. You may also obtain copies of this information by mail from the Public Reference Section of the SEC, 100 F Street, N.E., Washington, D.C. 20549, at prescribed rates. You may obtain information on the operation of the SEC’s Public Reference Room in Washington, D.C. by calling the SEC at 1-800-SEC-0330. The SEC also maintains an Internet web site that contains reports, proxy and information statements and other information about issuers, like us, that file electronically with the SEC. The address of that site is http://www.sec.gov. The SEC file number for documents Comerica files under the Exchange Act is 001-10706. The reports and other information Comerica files with the SEC also are available at Comerica’s website, www.comerica.com. We have included the SEC’s web address and our web address as inactive textual references only. Except as specifically incorporated by reference into this prospectus, information on those websites is not part of this prospectus.

Comerica is allowed to “incorporate by reference” the information Comerica files with the SEC, which means that it can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus, and information that Comerica files subsequently with the SEC will automatically update and supersede the information included and/or incorporated by reference in this prospectus. Comerica incorporates by reference the documents listed below and any future filings made with the SEC (other than portions of these documents that are furnished under Item 2.02 or Item 7.01 of a Current Report on Form 8-K, including any exhibits included with such Items, or other information deemed to have been “furnished” rather than filed in accordance with the SEC’s rules) under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, after the initial filing of

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the Registration Statement that contains this prospectus and prior to the time that Comerica sells all of the securities offered by this prospectus:

Upon written or oral request, we will provide — at no cost to the requester — a copy of any or all of the information that has been incorporated by reference in this prospectus but not delivered with this prospectus (other than exhibits, unless that exhibit is specifically incorporated by reference into that filing). You may make a request by writing to the following address or calling the following telephone number:

Investor Relations

Comerica Incorporated

Comerica Bank Tower

1717 Main Street

Dallas, Texas 75201

Telephone number: (214) 462-6831

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Comerica Incorporated

Depositary Shares, Each Representing a 1/100th

Interest in a Share of     % Fixed-Rate Reset

Non-Cumulative Perpetual Preferred Stock, Series A

Joint Book-Running Managers

J.P. Morgan

BofA Securities

Morgan Stanley

RBC Capital Markets

Co-Manager

Comerica Securities