Prospectus Filed Pursuant to Rule 424(b)(3) (424b3)

Filed pursuant to Rule 424(b)(3)

Registration No. 333-257496

PROSPECTUS SUPPLEMENT NO. 11

(to Prospectus dated July 9, 2021)

Proterra Inc

161,169,124 Shares of Common Stock

28,941,556 Shares of Common Stock Underlying Warrants and Convertible Notes

____________________

This prospectus supplement supplements the prospectus dated July 9, 2021, as supplemented by Prospectus Supplement No. 1, dated August 11, 2021, Prospectus Supplement No. 2, dated August 13, 2021, Prospectus Supplement No. 3, dated September 8, 2021, Prospectus Supplement No. 4, dated September 13, 2021, Prospectus Supplement No. 5, dated October 15, 2021, Prospectus Supplement No. 6, dated November 12, 2021, Prospectus Supplement No. 7, dated December 9, 2021, Prospectus Supplement No. 8, dated December 16, 2021, Prospectus Supplement No. 9, dated January 24, 2022, and Prospectus Supplement No. 10, dated February 23, 2022 (the “Prospectus”), which forms a part of our registration statement on Form S-1 (No. 333-257496). This prospectus supplement is being filed to update and supplement the information in the Prospectus with the information contained in our Notification of Late Filing on Form 12b-25 for our Annual Report on Form 10-K for the year ended December 31, 2021, filed with the Securities and Exchange Commission on March 2, 2022. Accordingly, we have attached the Form 12b-25 to this prospectus supplement.

The Prospectus and this prospectus supplement relate to the offer and sale from time to time by the selling securityholders named in the Prospectus (the “Selling Securityholders”) of up to 161,169,124 shares of common stock, par value $0.0001 per share (“common stock”), consisting of (i) up to 41,500,000 shares of common stock issued in a private placement pursuant to subscription agreements entered into on January 11, 2021; (ii) up to 6,797,072 shares of common stock issued in connection with the consummation of the Business Combination (as defined in the Prospectus), in exchange for shares of our Class B ordinary shares originally issued in a private placement to ArcLight CTC Holdings, L.P. (the “Sponsor”); and (iii) up to 112,872,052 shares of common stock issued or issuable to certain former stockholders and other security holders of Proterra (the “Proterra Holders”) in connection with or as a result of the consummation of the Business Combination, consisting of (a) up to 60,006,701 shares of common stock; (b) up to 25,437,033 shares of common stock (the “Note Shares”) issuable upon the conversion of outstanding convertible promissory notes (the “Convertible Notes”); (c) up to 3,504,523 shares of common stock issuable upon the exercise of certain warrants (the “Proterra warrants”); (d) 11,111,287 shares of common stock issuable upon the exercise of certain equity awards; and (e) up to 12,895,129 shares of common stock that certain Proterra Holders have the contingent right to receive upon the achievement of certain stock price-based vesting conditions.

In addition, the Prospectus and this prospectus supplement relates to the offer and sale of (i) up to 3,504,523 shares of common stock issuable by us upon exercise of the Proterra warrants that were previously registered, and (ii) up to 25,437,033 Note Shares issuable by us upon conversion of the Convertible Notes, certain of which were previously registered.

Our common stock is listed on the Nasdaq Global Select Market (the “Nasdaq”) under the symbol “PTRA”. On March 1, 2022, the last reported sales price of our common stock was $8.23 per share.

This prospectus supplement updates and supplements the information in the Prospectus and is not complete without, and may not be delivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This prospectus supplement should be read in conjunction with the Prospectus and if there is any inconsistency between the information in the Prospectus and this prospectus supplement, you should rely on the information in this prospectus supplement.

Investing in our common stock involves risks. See the section entitled “Risk Factors” beginning on page 56 of the Prospectus to read about factors you should consider before buying our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the Prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is March 2, 2022



Commission File Number 001-39546


CUSIP Number 74374T109

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 12b-25

NOTIFICATION OF LATE FILING


(Check One)			☒ Form 10-K ☐ Form 20-F ☐ Form 11-K ☐ Form 10-Q
			☐ Form 10-D ☐ Form N-CSR

For Period Ended: December 31, 2021

☐ Transition Report on Form 10-K

☐ Transition Report on Form 20-F

☐ Transition Report on Form 11-K
☐ Transition Report on Form 10-Q

For the Transaction Period ended: _______________

___________________



Nothing in this form shall be construed to imply that the Commission has verified any information contained herein.

If the notification relates to a portion of the filing checked above, identify the Item(s) to which the notification relates:

PART I - REGISTRANT INFORMATION



Proterra Inc
Full Name of Registrant


Former Name if Applicable
1815 Rollins Road
Address of Principal Executive Office (Street and number)
Burlingame, California 94010
City, State and Zip Code

PART II - RULES 12b-25(b) and (c)

If the subject report could not be filed without unreasonable effort or expense and the registrant seeks relief pursuant to Rule 12b-25(b), the following should be completed. (Check box if appropriate)


☒			(a) The reason described in reasonable detail in Part III of this form could not be eliminated without unreasonable effort or expense;
☒			(b) The subject annual report, semi-annual report, transition report on Form 10-K, Form 20-F, Form 11-K or Form N-CSR, or portion thereof, will be filed on or before the fifteenth calendar day following the prescribed due date; or the subject quarterly report or transition report on Form 10-Q or subject distribution report on Form 10-D, or portion thereof, will be filed on or before the fifth calendar day following the prescribed due date; and
☐			(c) The accountant’s statement or other exhibit required by Rule 12b-25(c) has been attached if applicable.

PART III - NARRATIVE

State below in reasonable detail the reasons why Forms 10-K, 20-F, 11-K, 10-Q, 10-D, N-CSR, or the transition report or portion thereof, could not be filed with the prescribed time period.

Proterra Inc (the “Company”) is filing this Notification of Late Filing on Form 12b-25 (this “Form 12b-25”) with respect to its Annual Report on Form 10-K for its fiscal year ended December 31, 2021 (the “Annual Report”). The Company has determined that it is unable to file the Annual Report within the prescribed time period without unreasonable effort or expense because it requires additional time to complete its financial statement preparation and review process. The delay is due to staffing limitations at the Company exacerbated by Covid-19 pandemic related absences in the Company's finance team. As a result of the foregoing, KPMG LLP, the Company’s independent registered public accounting firm, has not yet completed its audit procedures. The Company believes that it will file the Annual Report on or before the fifteenth calendar day following the prescribed due date.

PART IV - OTHER INFORMATION


(1)			Name and telephone number of person to contact in regard to this notification



JoAnn C. Covington Chief Legal Officer and Secretary	(650)	689-8242
(Name)	(Area Code)	(Telephone Number)


(2)			Have all other periodic reports required under Section 13 or 15(d) of the Securities Exchange Act of 1934 or Section 30 of the Investment Company Act of 1940 during the preceding 12 months or for such shorter period that the registrant was required to file such reports been filed? If answer is no, identify report(s). ☒ Yes ☐ No


(3)			Is it anticipated that any significant change in results of operations from the corresponding period for the last fiscal year will be reflected by the earnings statements to be included in the subject report or portion thereof? ☒ Yes ☐ No

The Company expects to report total revenues of $242.9 million for the year ended December 31, 2021, compared to total revenues of $196.9 million for the year ended December 31, 2020. The Company expects to report a net loss of $250.0 million for the year ended December 31, 2021, compared to a net loss of $127.0 million for the year ended December 31, 2020. The increase in net loss was as a result of, among other things, increased total cost of goods sold of $240.8 million in 2021 compared to $189.4 million in 2020, increased total operating expenses of $129.7 million in 2021 compared to $103.5 million in 2020, and increased loss on valuation of derivative and warrant liabilities of $70.2 million in 2021 compared to $13.0 million in 2020. The foregoing figures are preliminary and unaudited and are prepared in accordance with U.S. generally accepted accounting principles.

The Company does not expect any changes to the preliminary unaudited financial results reported above or to the preliminary financial results previously reported in its quarterly letter to stockholders furnished as Exhibit 99.1 to the Company's Current Report on Form 8-K filed on March 1, 2022, however results may be subject to change after the completion of year end reviews and the completion of the audit.

Cautionary Note Regarding Forward Looking Statements.

Certain statements in this Form 12b-25 constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements in this Form 12b-25 that do not relate to matters of historical fact should be considered forward-looking statements, including statements regarding the Company's expectation that it will fill the Annual Report within the time period prescribed by Rule 12b-25, the Company's expectations regarding its financial results reported in this Form 12b-25 and as furnished as Exhibit 99.1 to the Company's Current Report on Form 8-K filed on March 1, 2022. Many factors could cause actual future events to differ materially from the forward-looking statements, including risks and uncertainties set forth in the sections entitled “Risk Factors” in the Company's prospectus dated July 9, 2021, filed with the U.S. Securities and Exchange Commission on July 9, 2021. These forward-looking statements are based on management's expectations as of the date of this filing.

Proterra Inc


(Name of Registrant as Specified in Charter)

has caused this notification to be signed on its behalf by the undersigned hereunto duly authorized.



Date:	March 1, 2022	By:	/s/ Karina Franco Padilla
		Name:	Karina Franco Padilla
		Title:	Chief Financial Officer

INSTRUCTION: The form may be signed by an executive officer of the registrant or by any other duly authorized representative. The name and title of the person signing the form shall be typed or printed beneath the signature. If the statement is signed on behalf of the registrant by an authorized representative (other than an executive officer), evidence of the representative’s authority to sign on behalf of the registrant shall be filed with the form.

ATTENTION