Twist Bioscience (TWST) director’s 10b5-1 option exercise and 10K share sale

Rhea-AI Filing Summary

Twist Bioscience director Robert Chess exercised stock options for 10,000 shares of Common Stock at $11.89 per share and on the same day sold 10,000 shares at $47.00 per share in an open-market transaction. These transactions were carried out under a pre-arranged Rule 10b5-1 trading plan adopted on December 10, 2025, indicating they were scheduled in advance. After the sale, he holds 21,084 shares directly and 42,528 shares indirectly through the Chess 1997 Trust, where he and his spouse are the sole trustees and beneficiaries.

Insights

Equity compensation and insider-trading analyst

Pre-planned option exercise and sale with substantial holdings retained.

Director Robert Chess exercised options for 10,000 shares of Twist Bioscience Common Stock at $11.89 and sold 10,000 shares at $47.00. This is a classic exercise-and-sell pattern converting an option position into cash rather than an outright open-market purchase or discretionary sale.

The filing states these trades were executed under a Rule 10b5-1 trading plan adopted on December 10, 2025, suggesting they were pre-scheduled and not timed opportunistically. After the transactions, Chess still holds 21,084 shares directly and 42,528 shares indirectly via the Chess 1997 Trust, so he maintains a meaningful equity stake.

Because the activity is compensation-related, pre-planned, and leaves significant direct and indirect ownership in place, it typically carries limited signaling value about the company’s prospects. Subsequent company filings may provide additional context on any future equity compensation or plan activity.

Insider Trade Summary 10b5-1

Net Seller: 10,000 shares ($470,000)

Net Sell 4 txns

Insider CHESS ROBERT

Role Director

Sold 10,000 shs ($470K)

Type	Security	Shares	Price	Value
Exercise	Stock Option (right to buy)	10,000	$0.00	--
Exercise	Common Stock	10,000	$11.89	$119K
Sale	Common Stock	10,000	$47.00	$470K
holding	Common Stock	--	--	--

Holdings After Transaction: Stock Option (right to buy) — 18,417 shares (Direct); Common Stock — 31,084 shares (Direct); Common Stock — 42,528 shares (Indirect, By the Chess 1997 Trust)

Footnotes (1)

1. The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan previously adopted by the Reporting Person on December 10, 2025. The Reporting Person and his spouse are the sole trustees and the sole beneficiaries of the Chess 1997 Trust. The option is immediately exercisable. 10% of the shares subject to the option vested on September 13, 2018, 15% of the shares subject to the option vested on March 24, 2019, and 1/48th of the shares subject to the option vested on each monthly anniversary thereafter, subject to the Reporting Person's continuous service through each vesting date.

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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).

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^*

CHESS ROBERT

(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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/17/2026

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	03/17/2026		M(1)		10,000	A	$11.89	31,084	D
Common Stock	03/17/2026		S(1)		10,000	D	$47	21,084	D
Common Stock								42,528	I	By the Chess 1997 Trust(2)

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
Stock Option (right to buy)	$11.89	03/17/2026		M(1)			10,000	(3)	09/13/2028	Common Stock	10,000	$0	18,417	D

Explanation of Responses:

1. The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan previously adopted by the Reporting Person on December 10, 2025.

2. The Reporting Person and his spouse are the sole trustees and the sole beneficiaries of the Chess 1997 Trust.

3. The option is immediately exercisable. 10% of the shares subject to the option vested on September 13, 2018, 15% of the shares subject to the option vested on March 24, 2019, and 1/48th of the shares subject to the option vested on each monthly anniversary thereafter, subject to the Reporting Person's continuous service through each vesting date.

Remarks:

	/s/ Kendra Fox, as Attorney-in-Fact for Robert Chess	03/19/2026
	** 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 insider transaction did Twist Bioscience (TWST) director Robert Chess report?

Director Robert Chess reported exercising options for 10,000 shares of Twist Bioscience Common Stock at $11.89 per share and selling 10,000 shares at $47.00. The combined activity reflects an option exercise followed by an open-market sale on the same date.

Was the Twist Bioscience (TWST) insider trade by Robert Chess pre-planned under a Rule 10b5-1 plan?

Yes. The filing states the transactions were executed under a Rule 10b5-1 trading plan adopted on December 10, 2025. Such plans pre-schedule trades, making their timing more routine and reducing their informational value about short-term company prospects.

How many Twist Bioscience (TWST) shares does Robert Chess hold after this Form 4?

Following the reported transactions, Robert Chess holds 21,084 Twist Bioscience shares directly. He also has indirect ownership of 42,528 shares through the Chess 1997 Trust, where he and his spouse are the sole trustees and beneficiaries.

What prices were involved in Robert Chess’s Twist Bioscience (TWST) option exercise and share sale?

The stock options were exercised at a conversion price of $11.89 per share, creating 10,000 shares of Common Stock. Those 10,000 shares were then sold in the open market at a reported transaction price of $47.00 per share.

What type of equity award did Robert Chess exercise at Twist Bioscience (TWST)?

He exercised a stock option, described as a “Stock Option (right to buy)” for 10,000 underlying shares of Common Stock at $11.89 per share. Footnotes explain the option vested over time and was immediately exercisable at the date of this transaction.

How is the Chess 1997 Trust related to Robert Chess’s Twist Bioscience (TWST) holdings?

The Chess 1997 Trust holds 42,528 Twist Bioscience shares reported as indirect ownership. The filing notes that Robert Chess and his spouse are the sole trustees and sole beneficiaries of the trust, so these shares are attributed to him as indirect holdings.