Tax-withholding share sale by Adaptive Biotechnologies (NASDAQ: ADPT) CCO

Rhea-AI Filing Summary

Adaptive Biotechnologies Corp reported that Chief Commercial Officer, MRD, Susan Bobulsky sold 41,338 shares of common stock on March 11, 2026 at an average price of $13.17 per share. According to the disclosure, this transaction was required to cover tax withholding obligations related to vesting restricted stock units and was executed under a mandatory “sell to cover” election, meaning it was not a discretionary trade. Following the sale, Bobulsky directly holds 427,775 shares of Adaptive Biotechnologies common stock.

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

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

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^*

BOBULSKY SUSAN

(Last) (First) (Middle)

C/O ADAPTIVE BIOTECHNOLOGIES CORPORATION

1165 EASTLAKE AVENUE EAST

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Commercial Officer, MRD

3. Date of Earliest Transaction (Month/Day/Year)
03/11/2026

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	03/11/2026		S(1)		41,338	D	$13.17	427,775	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. This transaction represents the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of RSUs. This sale is mandated by the Issuer's election under its equity incentive plans to require the satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary trade by the Reporting Person.

	Susan Bobulsky by Kyle Piskel, Attorney-in-Fact	03/13/2026
	** Signature of Reporting Person	Date
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FAQ

What insider transaction did Adaptive Biotechnologies (ADPT) report for Susan Bobulsky?

Adaptive Biotechnologies reported a sale of 41,338 shares of common stock by Chief Commercial Officer, MRD, Susan Bobulsky at $13.17 per share. The shares were sold to satisfy tax withholding obligations tied to vesting RSUs under a mandatory “sell to cover” arrangement.

Was the recent ADPT insider share sale by Susan Bobulsky discretionary?

No, the sale was not discretionary. The company states the 41,338 shares were sold solely to cover tax withholding obligations from RSU vesting, under an issuer-mandated “sell to cover” plan, rather than as an elective open-market trade by the executive.

How many Adaptive Biotechnologies (ADPT) shares does Susan Bobulsky hold after the sale?

After the transaction, Susan Bobulsky holds 427,775 shares of Adaptive Biotechnologies common stock directly. This figure reflects her remaining position once 41,338 shares were sold to fund required tax withholding on recently vesting restricted stock units.

At what price were the ADPT shares sold in Susan Bobulsky’s Form 4 filing?

The reported sale price was $13.17 per share. On March 11, 2026, 41,338 Adaptive Biotechnologies common shares were sold at this average price to cover RSU-related tax obligations, under the company’s equity incentive plan procedures.

Does Susan Bobulsky’s ADPT share sale signal a change in insider sentiment?

The filing characterizes the sale as tax-related rather than strategic. Shares were sold to satisfy RSU tax withholding through a required “sell to cover” transaction, which is typically viewed as administrative and less indicative of changing views on the company’s prospects.