Adaptive Biotechnologies (ADPT) CFO executes mandated 18,672-share sale for RSU tax withholding

Rhea-AI Filing Summary

Adaptive Biotechnologies Corp Chief Financial Officer Kyle Piskel reported a mandated sale of 18,672 shares of Common Stock on March 11, 2026. The shares were sold at an average price of $13.17 per share and were executed as an open-market transaction.

According to the disclosure, this sale was required to cover tax withholding obligations triggered by the vesting of restricted stock units under the company’s equity incentive plans. The footnote states the transaction was a “sell to cover” and not a discretionary trade by Piskel. After the sale, he directly holds 259,840 shares of Adaptive Biotechnologies Corp common stock.

Insights

Equity compensation and insider-trading analyst

Sale is tax-driven, routine, and not a discretionary insider trade.

The transaction shows Adaptive Biotechnologies CFO Kyle Piskel selling 18,672 common shares at $13.17 each. However, the footnote explains this was a mandatory “sell to cover” to satisfy tax withholding on RSU vesting under the company’s equity plans.

Because the sale is mechanically tied to equity compensation taxes, it carries little informational value about Piskel’s view of the stock. He retains 259,840 shares afterward, indicating this represents a relatively small portion of his disclosed holdings. Overall, this is a routine, compensation-related event rather than a thesis-changing signal.

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
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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^*

PISKEL KYLE

(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 Financial Officer

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)		18,672	D	$13.17	259,840	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.

	/s/ Kyle Piskel	03/13/2026
	** 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.

FAQ

What insider transaction did Adaptive Biotechnologies (ADPT) disclose for Kyle Piskel?

Adaptive Biotechnologies disclosed that CFO Kyle Piskel sold 18,672 shares of common stock. The shares were sold on March 11, 2026, at an average price of $13.17 per share in a transaction tied to tax withholding on vested RSUs.

Was Kyle Piskel’s sale of ADPT shares a discretionary trade?

No, the filing states the sale was not discretionary. It was mandated as a “sell to cover” transaction to fund tax withholding obligations arising from the vesting of restricted stock units under Adaptive Biotechnologies’ equity incentive plans.

How many Adaptive Biotechnologies (ADPT) shares did Kyle Piskel sell and at what price?

Kyle Piskel sold 18,672 shares of Adaptive Biotechnologies common stock. The shares were sold at an average price of $13.17 per share in an open-market transaction associated with covering tax withholding on RSU vesting.

How many ADPT shares does CFO Kyle Piskel hold after this Form 4 transaction?

Following the reported transaction, CFO Kyle Piskel directly holds 259,840 shares of Adaptive Biotechnologies common stock. This indicates that the 18,672 shares sold for tax withholding represent only a portion of his overall disclosed equity position.

What is the significance of the footnote on Kyle Piskel’s ADPT share sale?

The footnote explains the sale covers tax withholding obligations from RSU vesting and is mandated by the company’s equity plans. It clarifies the sale is a “sell to cover” and does not represent a discretionary trading decision by Kyle Piskel.