Adaptive Biotechnologies (ADPT) CFO tax-related share sale leaves 256,725 shares held

Rhea-AI Filing Summary

Adaptive Biotechnologies Corp Chief Financial Officer Kyle Piskel executed a small mandated share sale tied to equity compensation taxes. On May 18, 2026, he sold 3,115 shares of common stock at $13.04 per share to cover tax withholding obligations from vesting restricted stock units. The company’s equity incentive plan required this “sell to cover” transaction, and the footnote states it was not a discretionary trade. After the sale, Piskel directly held 256,725 shares of Adaptive Biotechnologies common stock.

Insider Trade Summary

Net Seller: 3,115 shares ($40,620)

Net Sell 1 txn

Insider PISKEL KYLE

Role Chief Financial Officer

Sold 3,115 shs ($41K)

Type	Security	Shares	Price	Value
Sale	Common Stock	3,115	$13.04	$41K

Holdings After Transaction: Common Stock — 256,725 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares sold: 3,115 shares Sale price per share: $13.04 per share Shares held after transaction: 256,725 shares

3 metrics

Shares sold 3,115 shares Common Stock sold on May 18, 2026

Sale price per share $13.04 per share Open-market sale used to cover tax withholding

Shares held after transaction 256,725 shares Directly owned by CFO after May 18, 2026 sale

Key Terms

tax withholding obligations, RSUs, equity incentive plans, sell to cover

4 terms

tax withholding obligations financial

"shares required to be sold ... to cover tax withholding obligations in connection with the vesting of RSUs"

RSUs financial

"cover tax withholding obligations in connection with the vesting of RSUs"

RSUs, or restricted stock units, are a form of company shares given to employees as part of their compensation. They are typically awarded with certain restrictions, such as a waiting period before they can be fully owned or sold, similar to earning a gift that becomes fully yours over time. For investors, RSUs can impact a company's stock offerings and reflect how much the company relies on stock-based incentives to attract and retain talent.

equity incentive plans financial

"mandated by the Issuer's election under its equity incentive plans to require the satisfaction of tax withholding obligations"

Equity incentive plans are company programs that pay employees, executives, or directors with company stock, stock options, or share units instead of or in addition to cash, aiming to align their interests with shareholders—like giving team members a stake in the house they help build. For investors this matters because such plans can motivate better company performance but also dilute existing ownership and increase reported compensation costs, so they affect future earnings, voting power, and share value.

sell to cover financial

"funded by a "sell to cover" transaction and does not represent a discretionary trade"

Sell to cover is when a person who receives company stock through options or awards sells just enough shares immediately to pay required taxes, exercise costs, or fees, keeping the rest. Think of it like cashing part of a bonus to cover the tax bill so you can keep the remainder. For investors, it can create predictable small selling pressure and slightly change the number of shares actually held by insiders without increasing long‑term dilution.

Form 4 Insider Transactions: What Each Field Means →

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).

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 WASHINGTON 98109

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/18/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	05/18/2026		S(1)		3,115	D	$13.04	256,725	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	05/20/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What did Adaptive Biotechnologies (ADPT) CFO Kyle Piskel do in this Form 4?

Adaptive Biotechnologies CFO Kyle Piskel reported selling 3,115 shares of common stock. The transaction covered tax withholding obligations from vesting RSUs under the company’s equity incentive plan and was structured as a required “sell to cover” rather than a discretionary market sale.

How many Adaptive Biotechnologies (ADPT) shares did the CFO sell and at what price?

Kyle Piskel sold 3,115 shares of Adaptive Biotechnologies common stock at $13.04 per share. This sale was specifically to satisfy tax withholding obligations associated with restricted stock unit vesting, as described in the Form 4 footnote, rather than an elective portfolio decision.

Why was the Adaptive Biotechnologies (ADPT) CFO’s share sale characterized as a tax-related transaction?

The Form 4 footnote explains the shares were sold to cover tax withholding obligations arising from RSU vesting. It notes the sale was mandated by the issuer’s equity incentive plan as a “sell to cover” transaction and explicitly states it does not represent a discretionary trade by the CFO.

How many Adaptive Biotechnologies (ADPT) shares does the CFO hold after this transaction?

Following the tax-related sale, CFO Kyle Piskel directly holds 256,725 shares of Adaptive Biotechnologies common stock. This post-transaction holding level, reported in the Form 4, shows that the 3,115 shares sold represent a small portion of his overall equity position in the company.

Was the Adaptive Biotechnologies (ADPT) CFO’s Form 4 sale considered an open-market trade?

The Form 4 uses the sale code but its footnote clarifies the transaction’s purpose was tax withholding for RSU vesting. While executed as a sale, it was mandated under the company’s equity incentive plans and is described as not being a discretionary open-market trade by the CFO.