HALO Halozyme Therapeutics Incorporated

Indenture

On November 18, 2019, Halozyme Therapeutics, Inc. (the “Company,” “we,” “us” or “our”) completed its previously announced sale of $400.0 million in aggregate principal amount of 1.25% Convertible Senior Notes due 2024 (the “ Convertible Notes”) in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”). The Convertible Notes were issued under an indenture, dated as of November 18, 2019, (the “Indenture”) between the Company and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”). In addition, the initial purchasers of the Convertible Notes (the “Initial Purchasers”) exercised their option to purchase an additional $60.0 million in aggregate principal amount of the Convertible Notes. The offer and sale of the Convertible Notes and the shares of common stock issuable upon conversion of the Convertible Notes have not been registered under the Securities Act, or the securities laws of any other jurisdiction, and the Convertible Notes and such shares may not be offered or sold absent registration or an applicable exemption from registration requirements, or in a transaction not subject to, such registration requirements.

The Company received net proceeds from the offering of approximately $446.9 million. The Company plans to use up to $200.0 million of the net proceeds from the offering to repurchase shares of the Company’s common stock, including approximately $143.1 million to repurchase approximately 8.1 million shares of its common stock concurrently with the offering in privately negotiated transactions effected through one or more of the Initial Purchasers or an affiliate thereof and $50 million to repurchase approximately 2.1 million shares of its common stock, pursuant to and subject to adjustment as provided in the ASR Agreement as described below.

The Company used approximately $26.1 million of the net proceeds from the offering to repay all outstanding amounts under its loan agreement with Oxford Finance and Silicon Valley Bank and intends to use the remainder of the net proceeds for general corporate purposes, including additional share repurchases subsequent to the offering and working capital.

The Convertible Notes will pay interest semi-annually in arrears on June 1st and December 1st of each year, beginning on June 1, 2020, at an annual rate of 1.25% and will be convertible into cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election, based on the applicable conversion rate at such time. The Convertible Notes are general unsecured obligations of the Company and will rank senior in right of payment to all of the Company’s indebtedness that is expressly subordinated in right of payment to the Convertible Notes, will rank equally in right of payment with all of the Company’s existing and future liabilities that are not so subordinated, will be effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness and will be structurally subordinated to all indebtedness and other liabilities (including trade payables) of the Company’s current or future subsidiaries.

Holders may convert their Convertible Notes at their option only in the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on March 31, 2020, if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price for each of at least 20 trading days during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (2) during the five consecutive business days immediately after any five consecutive trading day period (such five consecutive trading day period, the “measurement period”) in which the trading price per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of Company’s common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on Company’s common stock, as described in the offering memorandum; (4) if we call such notes for redemption; and (5) at any time from, and including, June 1, 2024 until the close of business on the scheduled trading day immediately before the maturity date. The Convertible Notes will be convertible, regardless of the foregoing circumstances, at any time from, and including, June 1, 2024 until the close of business on the scheduled trading day immediately preceding the maturity date.

Upon conversion, the Company will pay or deliver, as applicable, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election. The initial conversion rate for the Convertible Notes will be 41.9208 shares of common stock per $1,000 in principal amount of Convertible Notes, equivalent to a conversion price of approximately $23.85 per share of our common stock. The conversion rate is subject to adjustment as described in the Indenture.

Subject to certain exceptions, holders may require the Company to repurchase, for cash, all or any portion thereof in an authorized denomination of their Convertible Notes upon a “Fundamental Change” (as defined in the Indenture) at a price equal to 100% of the principal amount of the Convertible Notes being repurchased plus any accrued and unpaid interest, if any, up to, but excluding, the “Fundamental Change Repurchase Date” (as

defined in the Indenture). In addition, upon a “Make-Whole Fundamental Change” (as defined in the Indenture) prior to the maturity date of the Convertible Notes, the Company will, in certain circumstances, increase the conversion rate for a specified period of time. The Company may not redeem the Convertible Notes prior to December 1, 2022 and on or before the 40th scheduled trading day immediately before the maturity date.

The Indenture includes customary covenants, and sets forth certain events of default after which the Convertible Notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving the Company or certain of its subsidiaries after which the Convertible Notes become automatically due and payable.

The foregoing description of the Indenture and Convertible Notes is qualified in its entirety by reference to the text of the Indenture and the Form of Convertible Note, copies of which are attached as Exhibits 4.1 and 4.2, respectively, to this Current Report on Form 8-K and are incorporated herein by reference.