TNDM Tandem Diabetes Care Inc

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 OF SECURITIES                                                                                   
OMB APPROVAL
OMB Number: 3235-0287
Estimated average burden
hours per response... 0.5                       
Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940                       

1. Name and Address of Reporting Person * TWOMEY CHRISTOPHER J	2. Issuer Name and Ticker or Trading Symbol TANDEM DIABETES CARE INC [ TNDM ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director                    _____ 10% Owner _____ Officer (give title below)    _____ Other (specify below)
(Last)          (First)          (Middle) C/O TANDEM DIABETES CARE, INC., 11075 ROSELLE STREET	3. Date of Earliest Transaction (MM/DD/YYYY) 7/29/2021
(Street) SAN DIEGO, CA 92121 (City)        (State)        (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	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. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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	7/29/2021		S(1)		5000	D	$105	15032	I	See Footnote (2)
Common Stock	7/29/2021		G(3)		2500	D	$104.885 (4)	12532	I	See Footnote (2)
Common Stock	7/29/2021		S(1)		3000	D	$105	11523	I	See Footnotes (5)
Common Stock								1892	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		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 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

Explanation of Responses:
(1)	The shares were sold, pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 9, 2021.
(2)	The securities are held by the Chris J. Twomey and Rebecca J. Twomey Family Trust UTD September 20, 2002.
(3)	The shares were given as a bona fide gift to the Chris and Rebecca Twomey Family Foundation at the San Diego Foundation.
(4)	The price per share reflects the average of the high and low trading prices of the Company's stock on the transaction date.
(5)	The securities are directly owed by Twomey Family Investments, LLC. The Reporting Person is co-manager of Twomey Family Investments, LLC and shares voting and investment power over the securities held by Twomey Family Investments, LLC and may be deemed to have indirect beneficial ownership of such shares. The Reporting Person disclaims beneficial ownership of such securities held by Twomey Family Investments, LLC, except to the extent of his proportionate pecuniary interest therein.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
TWOMEY CHRISTOPHER J C/O TANDEM DIABETES CARE, INC. 11075 ROSELLE STREET SAN DIEGO, CA 92121	X

Signatures
s/ David B. Berger, Attorney-in-Fact for Christopher J. Twomey		7/30/2021
**Signature of Reporting Person		Date