Sec Form 4 Filing - Calcaterra Chris M. @ GLAUKOS Corp - 2021-03-18

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Calcaterra Chris M. 2. Issuer Name and Ticker or Trading Symbol GLAUKOS Corp [ GKOS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Operating Officer (Last) (First) (Middle) C/O GLAUKOS CORPORATION,, 229 AVENIDA FABRICANTE 3. Date of Earliest Transaction (MM/DD/YY) 03/18/2021 (Street) SAN CLEMENTE, CA92672 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 03/18/2021 A 15,499 ( 1 ) A $ 0 179,305 ( 2 ) D Common Stock 03/18/2021 F 783 ( 3 ) D $ 89.22 178,522 ( 4 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Options (Right to Buy) $ 39.1 03/18/2021 A 6,384 ( 5 ) 03/18/2021 03/12/2030 Common Stock 6,384 $ 0 6,384 D Stock Options (Right to Buy) $ 28.78 03/18/2021 A 4,562 ( 6 ) 03/18/2021 03/12/2030 Common Stock 4,562 $ 0 4,562 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Calcaterra Chris M. C/O GLAUKOS CORPORATION, 229 AVENIDA FABRICANTE SAN CLEMENTE, CA92672 Chief Operating Officer Signatures /s/ Diana Scherer, Attorney-in-Fact 03/22/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Granted by the Issuer in the form of restricted stock units which vest over a four-year period, with 25% to vest on each anniversary of the grant date. ( 2 )Includes 21,466 restricted stock units that have not yet vested or been delivered to the Reporting Person. ( 3 )Consists of shares withheld by the Issuer with respect to tax withholding obligations of the Reporting Person upon vesting and delivery of shares of common stock underlying restricted stock units previously granted by the Issuer on March 14, 2019. ( 4 )Includes 19,888 restricted stock units that have not yet vested or been delivered to the Reporting Person. ( 5 )Represents a portion of an option to purchase shares of common stock previously granted by the Issuer on March 12, 2020, the vesting of which was subject to the Issuer's achievement of certain multi-year performance goals. The Compensation Committee of the Issuer's Board of Directors (the "Compensation Committee") determined on March 18, 2021 the level of achievement for the first year of the multi-year performance period. The number of shares of common stock subject to the stock option as reported herein consists of the portion of the award that vested based upon the achievement with respect to the first-year performance goal. ( 6 )Represents an option to purchase shares of common stock previously granted by the Issuer on April 1, 2020 pursuant to the Reporting Person's election to receive a portion of his annual bonus for 2020 in the form of stock options rather than cash (the "Bonus Election"). The Compensation Committee determined on March 18, 2021 the annual bonus payable to the Reporting Person pursuant to the Issuer's 2020 executive bonus plan and the number of shares of common stock subject to the stock option earned by the Reporting Person in accordance with the Bonus Election, subject to continued employment through the vesting date. The option to purchase common stock will vest on April 1, 2021.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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