Adaptive Biotechnologies CEO sells 524,998 shares

Adaptive Biotechnologies Corp CEO and Chairman Chad M. Robins reported open-market sales of an aggregate 524,998 shares of common stock in late February and early March 2026 under a Rule 10b5-1 trading plan adopted on August 11, 2025.

Rhea-AI Filing Summary

Adaptive Biotechnologies Corp CEO and Chairman Chad M. Robins reported open-market sales of an aggregate 524,998 shares of common stock in late February and early March 2026 under a Rule 10b5-1 trading plan adopted on August 11, 2025. The shares were sold in multiple transactions at weighted average prices, with sale prices ranging from $15.11 to $16.23 per share. Following these transactions, Robins directly holds 1,934,247 shares of Adaptive Biotechnologies common stock.

Insider Trade Summary

Net Seller: 524,998 shares

Net Sell 4 txns

Insider ROBINS CHAD M

Role CEO and Chairman

Sold 524,998 shs ($8.32M)

Type	Security	Shares	Price	Value
Sale	Common Stock	50,703	$15.49	$785K
Sale	Common Stock	2,380	$16.15	$38K
Sale	Common Stock	289,024	$15.82	$4.57M
Sale	Common Stock	182,891	$15.99	$2.92M

Holdings After Transaction: Common Stock — 1,934,247 shares (Direct)

Footnotes (5)

1. F1. The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 11, 2025.
2. F2. The price reported for this transaction is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.83 to $16.20, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4.
3. F3. The price reported for this transaction is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.51 to $16.18, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4.
4. F4. The price reported for this transaction is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.11 to $16.10, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4.
5. F5. The price reported for this transaction is a weighted average price. These shares were sold in multiple transactions at prices ranging from $16.11 to $16.23, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4.

FAQ

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How many Adaptive Biotechnologies (ADPT) shares did CEO Chad Robins sell?

CEO Chad M. Robins sold an aggregate 524,998 shares of Adaptive Biotechnologies common stock. These transactions were reported as open-market sales across several days, reducing but not eliminating his direct ownership, which remains at 1,934,247 shares after the reported trades.

Over what dates did the ADPT CEO’s reported stock sales occur?

Chad M. Robins’ reported stock sales took place on February 27, 2026, March 2, 2026, and March 3, 2026. Each date involved open-market transactions in Adaptive Biotechnologies common stock executed under a pre-established Rule 10b5-1 trading plan.

At what prices did the Adaptive Biotechnologies CEO sell his shares?

The reported sales used weighted average prices, with individual trades occurring between $15.11 and $16.23 per share. Specific line items show average prices such as $15.49, $15.82, $15.99, and $16.15, reflecting multiple executions within those overall price ranges.

What is the CEO’s remaining stake in Adaptive Biotechnologies after these sales?

After completing the reported transactions, Chad M. Robins directly owns 1,934,247 shares of Adaptive Biotechnologies common stock. This post-transaction balance reflects his holdings following the aggregate sale of 524,998 shares across the three trading dates disclosed.

Were the ADPT CEO’s stock sales made under a Rule 10b5-1 plan?

Yes. The filing states that the transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by Chad M. Robins on August 11, 2025. Such plans allow pre-arranged trading schedules, helping separate personal trading decisions from day-to-day corporate developments.

What kind of transactions did Chad Robins report for his ADPT shares?

Chad M. Robins reported open-market sales of Adaptive Biotechnologies common stock, coded as “S” transactions. Each entry is identified as a non-derivative transaction representing sales in the open market or private transactions, according to the description provided in the filing.

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Accepted by SEC EDGAR 03/03/2026 - 07:51 PM Learn about SEC filing dates

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).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

ROBINS CHAD M

(Last) (First) (Middle)

C/O ADAPTIVE BIOTECHNOLOGIES CORPORATION

1165 EASTLAKE AVE E

(Street)

SEATTLE WA 98109

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Adaptive Biotechnologies Corp [ ADPT ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CEO and Chairman

3. Date of Earliest Transaction (Month/Day/Year)
02/27/2026

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	02/27/2026		S(1)		182,891	D	$15.99(2)	2,276,354	D
Common Stock	03/02/2026		S(1)		289,024	D	$15.82(3)	1,987,330	D
Common Stock	03/03/2026		S(1)		50,703	D	$15.49(4)	1,936,627	D
Common Stock	03/03/2026		S(1)		2,380	D	$16.15(5)	1,934,247	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 (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

Explanation of Responses:

1. The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 11, 2025.

2. The price reported for this transaction is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.83 to $16.20, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4.

3. The price reported for this transaction is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.51 to $16.18, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4.

4. The price reported for this transaction is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.11 to $16.10, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4.

5. The price reported for this transaction is a weighted average price. These shares were sold in multiple transactions at prices ranging from $16.11 to $16.23, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4.

	/s/ Chad M. Robins by Kyle Piskel, Attorney-in-Fact	03/03/2025
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.