Sec Form 3 Filing - Leal James @ TANDEM DIABETES CARE INC - 2021-06-02

FORM 3 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 Leal James 2. Issuer Name and Ticker or Trading Symbol TANDEM DIABETES CARE INC [ TNDM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP, Operations (Last) (First) (Middle) C/O TANDEM DIABETES CARE, INC., 11075 ROSELLE STREET 3. Date of Earliest Transaction (MM/DD/YY) 06/02/2021 (Street) SAN DIEGO, CA92121 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 3,596 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 Option ( 1 ) $ 251.34 ( 2 ) ( 3 ) Common Stock 835 D Stock Option ( 1 ) $ 251.34 ( 2 ) ( 3 ) Common Stock 59 D Stock Option ( 4 ) $ 150 ( 5 ) ( 3 ) Common Stock 1,301 D Stock Option ( 4 ) $ 150 ( 5 ) ( 3 ) Common Stock 8,798 D Stock Option ( 4 ) $ 119.2 ( 6 ) ( 3 ) Common Stock 800 D Stock Option ( 4 ) $ 119.2 ( 6 ) ( 3 ) Common Stock 1,459 D Stock Option ( 4 ) $ 69.5 ( 7 ) ( 3 ) Common Stock 3,390 D Stock Option ( 4 ) $ 9 ( 8 ) ( 3 ) Common Stock 468 D Stock Option ( 4 ) $ 51.5 ( 9 ) ( 3 ) Common Stock 40,000 D Stock Option ( 4 ) $ 82.34 ( 10 ) ( 3 ) Common Stock 11,436 D Restricted Stock Unit ( 4 ) $ 0 ( 11 ) ( 11 ) Common Stock 3,716 D Stock Option ( 4 ) $ 81.63 ( 12 ) ( 3 ) Common Stock 4,095 D Restricted Stock Unit ( 4 ) $ 0 ( 13 ) ( 13 ) Common Stock 2,681 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Leal James C/O TANDEM DIABETES CARE, INC. 11075 ROSELLE STREET SAN DIEGO, CA92121 SVP, Operations Signatures s/ David B. Berger, Attorney-in-Fact for James A. Leal 06/10/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Granted pursuant to the Tandem Diabetes Care, Inc. 2006 Stock Incentive Plan. ( 2 )The date of grant of the option was 01/30/2012. All shares subject to the option have vested. ( 3 )The expiration date for these options is 10 years from the date of grant. ( 4 )Granted pursuant to the Tandem Diabetes Care, Inc. 2013 Stock Incentive Plan, as amended, and the agreements related thereto (the "2013 Plan"). ( 5 )The date of grant of the option was 11/13/2013. All shares subject to the option have vested. ( 6 )The date of grant of the option was 05/21/2015. All shares subject to the option have vested. ( 7 )The date of grant of the option was 02/16/2016. All shares subject to the option have vested. ( 8 )The date of grant of the option was 05/17/2017. All shares subject to the option have vested. ( 9 )The date of grant of the option was 02/15/2019. 25% of the shares subject to the option vested on 02/15/2020 and the remainder vests in 36 equal monthly installments thereafter. ( 10 )The date of grant of the option was 05/27/2020. 25% of the shares subject to the option vested on 05/27/2021 and the remainder vests in 36 equal monthly installments thereafter. ( 11 )The date of Restricted Stock Unit ("RSU") grant was 05/27/2020. RSU vested as to twenty-five percent (25%) of the total number of shares subject to the RSU on the one year anniversary of the grant date, and the remaining shares shall vest in twelve (12) equal quarterly installments thereafter, subject to the terms of the 2013 Plan. Each RSU represents a contingent right to receive either one share of common stock of the Issuer or cash in lieu thereof, at the Issuer's discretion, in accordance with the terms of the 2013 Plan. ( 12 )The date of grant of the option was 05/18/2021. 25% of the shares subject to the option will vest on 05/18/2022 and the remainder vests in 36 equal monthly installments thereafter. ( 13 )The date of Restricted Stock Unit ("RSU") grant was 05/18/2021. RSU vest as to twenty-five percent (25%) of the total number of shares subject to the RSU on 05/15/2022, and the remaining shares shall vest in twelve (12) equal quarterly installments thereafter, subject to the terms of the 2013 Plan. Each RSU represents a contingent right to receive either one share of common stock of the Issuer or cash in lieu thereof, at the Issuer's discretion, in accordance with the terms of the 2013 Plan.

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