Twist Bioscience CAO sells 238 shares for taxes

Twist Bioscience’s chief accounting officer executed a small, mandatory share sale to cover taxes tied to vesting RSUs.

Rhea-AI Filing Summary

Twist Bioscience Corp (TWST) reported that Chief Accounting Officer Robert F. Werner sold 238 shares of common stock on September 8, 2026, at $122.624 per share. According to the company’s equity incentive plan, this was a mandatory “sell to cover” transaction to satisfy tax withholding on vesting RSUs, not a discretionary trade. After the sale, Werner held 44,399 shares directly.

Insider Trade Summary

Net Seller: 238 shares

Net Sell 1 txn

Insider WERNER ROBERT F.

Role Chief Accounting Officer

Sold 238 shs ($29K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1	238	$122.624	$29K

Holdings After Transaction: Common Stock — 44,399 shares (Direct)

Footnotes (1)

1. F1. Represents the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of Restricted Stock Units. These sales are mandated by the Issuer's election under its equity incentive plans to require the satisfaction of a tax withholding obligation to be funded by a "sell to cover" transaction and do not represent discretionary trades by the Reporting Person.

Key Figures

Shares sold: 238 shares Sale price per share: $122.624 per share Shares owned after transaction: 44,399 shares +1 more

4 metrics

Shares sold 238 shares Common stock sold on September 8, 2026 in a tax-related transaction

Sale price per share $122.624 per share Price for the 238 shares sold on September 8, 2026

Shares owned after transaction 44,399 shares Direct holdings of Robert F. Werner following the sale

Net shares sold in filing 238 shares Net sell volume across all reported transactions in this Form 4

Key Terms

Restricted Stock Units, tax withholding obligations, sell to cover

3 terms

Restricted Stock Units financial

"in connection with the vesting of Restricted Stock Units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

tax withholding obligations financial

"to cover tax withholding obligations in connection with the vesting"

sell to cover financial

"funded by a "sell to cover" transaction and do not represent"

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.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did TWST disclose in this Form 4?

Twist Bioscience disclosed that Chief Accounting Officer Robert F. Werner sold 238 shares of common stock on September 8, 2026, at $122.624 per share, in a transaction flagged as a mandatory tax “sell to cover” related to vesting RSUs.

Was the TWST insider sale by the Chief Accounting Officer discretionary?

No. The filing states the 238-share sale was mandated under Twist Bioscience’s equity incentive plans as a “sell to cover” transaction to fund tax withholding obligations from vesting Restricted Stock Units, and it does not represent discretionary trading by the officer.

How many TWST shares does the Chief Accounting Officer hold after this transaction?

After the September 8, 2026 sale, Chief Accounting Officer Robert F. Werner beneficially owned 44,399 shares of Twist Bioscience common stock directly, as reported in the Form 4 following the tax-related “sell to cover” transaction.

What price was received for the TWST shares sold in this Form 4?

The 238 shares of Twist Bioscience common stock were sold at a price of $122.624 per share on September 8, 2026, in an open market or private transaction characterized as a mandatory tax withholding “sell to cover.”

Does the TWST Form 4 indicate use of a Rule 10b5-1 trading plan?

No. The filing’s Rule 10b5-1 checkbox is not marked as an affirming trading plan, and the footnote characterizes the transaction instead as a mandatory tax-related “sell to cover” under Twist Bioscience’s equity incentive plans.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/10/2026 - 04:00 PM EDT Accepted by SEC EDGAR 09/10/2026 - 04:00 PM EDT 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).

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^*

WERNER ROBERT F.

(Last) (First) (Middle)

C/O TWIST BIOSCIENCE CORPORATION

681 GATEWAY BLVD

(Street)

SOUTH SAN FRANCISCO CALIFORNIA 94080

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Twist Bioscience Corp [ TWST ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Accounting Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/08/2026

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	09/08/2026		S		238(1)	D	$122.624	44,399	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. Represents the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of Restricted Stock Units. These sales are mandated by the Issuer's election under its equity incentive plans to require the satisfaction of a tax withholding obligation to be funded by a "sell to cover" transaction and do not represent discretionary trades by the Reporting Person.

Remarks:

	/s/ Kendra Fox, as Attorney-in-Fact for Robert F. Werner	09/10/2026
	** 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)