SEC Form 4

FORM 4		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 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Vosseller Leigh (Last) (First) (Middle) C/O TANDEM DIABETES CARE, INC. 11075 ROSELLE STREET (Street) SAN DIEGO CA 92121 (City) (State) (Zip)	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) EVP & CHIEF FINANCIAL OFFICER
	3. Date of Earliest Transaction (Month/Day/Year) 05/17/2021
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	05/17/2021		A		296(1)	A	$66.76	4,816	D
Common Stock								145	I	Leigh A. Vosseller Trust(2)

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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
Restricted Stock Unit(3)	(4)	05/18/2021		A		2,599		(5)	(5)	Common Stock	2,599	$0	2,599	D
Performance Stock Unit(3)	(6)	05/18/2021		A		2,599		(6)	(6)	Common Stock	2,599	$0	2,599	D
Stock Option(3)	$81.63	05/18/2021		A		7,940		(7)	(8)	Common Stock	7,940	$0	7,940	D

Explanation of Responses:

1. The reporting person is voluntarily reporting the acquisition of shares of common stock pursuant to the Tandem Diabetes Care, Inc. Amended and Restated 2013 Employee Stock Purchase Plan ("ESPP"), for the ESPP purchase period of November 17, 2020 through May 17, 2021. This transaction is also exempt under Rule 16b-3(c).

2. The securities are held by the Leigh A. Vosseller Trust dated January 17, 2010, of which Leigh Vosseller is the Trustee.

3. Awarded on May 18, 2021 pursuant to the Tandem Diabetes Care, Inc. 2013 Stock Incentive Plan, as amended, and the agreements related thereto (the "2013 Plan").

4. Each restricted stock unit ("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.

5. RSU vest 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.

6. Each performance stock unit ("PSU") represents a contingent right to receive one share of Tandem Diabetes Care, Inc. (the "Company") common stock based upon the achievement of certain pre-defined performance metrics as of December 31, 2024 (the "Measurement Date"). The number of shares issued may range from 0% to 200 % of the amount specified above, based upon (i) Company's actual performance relative to the pre-defined performance metrics, and (ii) subject to the awardee's continuing service through the Measurement Date. If minimum performance metrics are not met, no PSU's will vest.

7. The option shall vest as to twenty-five percent (25%) of the underlying shares on the one-year anniversary of the grant date, and the remaining shares shall vest in thirty-six (36) equal monthly installments thereafter, subject to the terms of the 2013 Plan.

8. The expiration date for these options is 10 years from the date of grant.

Remarks:

	s/ David B. Berger, Attorney-in-Fact for Leigh A. Vosseller	05/20/2021
	** Signature of Reporting Person	Date
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).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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