TWST CEO executed 476-share tax-withholding sale; retains 632,560 shares

Rhea-AI Filing Summary

Emily M. Leproust, Chief Executive Officer and Director of Twist Bioscience Corporation (TWST), reported a small non-discretionary sale of shares to cover tax withholding related to vested restricted stock units. The filing shows a sale of $29.161 per share for 476 shares on 10/02/2025, described as a mandatory "sell to cover" to satisfy tax withholding; these sales were not discretionary trades by the reporting person. After the transaction, the reporting person beneficially owned 632,560 shares of common stock.

The Form 4 also lists outstanding employee stock options and performance options with various exercise prices and vesting/exercise dates, including options exercisable immediately and a granted performance option that vested on 12/19/2022. The report was signed by an attorney-in-fact on 10/06/2025.

Positive

• Insider sale was non-discretionary and conducted to cover tax withholding, reducing signaling risk
• Substantial remaining ownership with 632,560 shares retained by the CEO, indicating continued alignment with shareholders

Negative

• Outstanding options exist with exercise prices as low as $5.95, representing potential future dilution
• Some options are immediately exercisable, which could lead to stock issuance if exercised

Insights

Corporate Governance Expert

TL;DR: A routine, mandated "sell to cover" by the CEO reduced holdings by a small number of shares; ownership remains material.

The reported 476-share sale at $29.161 is explicitly described as a mandatory tax-withholding sale tied to vested restricted stock units, which governance best practices treat as non-discretionary and not indicative of a change in insider sentiment. The CEO still holds 632,560 shares, reflecting continued significant ownership.

Dependence on equity compensation remains a governance point to monitor because outstanding options with varying exercise prices and vesting schedules can cause future stock issuance or insider exercise activity; watch near-term vesting/expiration windows around 09/28/2025 through the listed expirations for any additional activity.

Equity Compensation Specialist

TL;DR: Multiple option grants and a vested performance option remain in place; most exercises are non-immediate or already exercised as disclosed.

The filing lists several employee stock options with exercise prices from $5.95 to $67.85 and shows 64,950 shares from a performance option exercisable following vesting on 12/19/2022. Two options are described as immediately exercisable and others vest on standard schedules, indicating ongoing equity dilution potential tied to future exercises.

Key items to watch are the counts and exercise prices of options that are currently exercisable versus those that are not; near-term dilution risk is limited given the small mandatory sale, but option exercises at lower strike prices could be dilutive if executed.

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^*

Leproust Emily M.

(Last) (First) (Middle)

C/O TWIST BIOSCIENCE CORPORATION

681 GATEWAY BLVD.

(Street)

SOUTH SAN FRANCISCO CA 94080

(City) (State) (Zip)

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
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

3. Date of Earliest Transaction (Month/Day/Year)
10/02/2025

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	10/02/2025		S		476(1)	D	$29.161	632,560	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
Employee Stock Option (right to buy)	$5.95							(2)	09/28/2025	Common Stock	0		0	D
Employee Stock Option (right to buy)	$8.82							(3)	09/28/2027	Common Stock	0		150,879	D
Employee Stock Option (right to buy)	$26.66							(4)	11/18/2028	Common Stock	0		266,539	D
Employee Stock Option (right to buy)	$23.33							(5)	10/23/2029	Common Stock	0		131,290	D
Employee Stock Option (right to buy)	$67.85							12/19/2022	08/31/2030	Common Stock	64,950		64,950(6)	D

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.

2. The option is immediately exercisable. 25% of the shares subject to the option vested on September 1, 2016 and 1/48th of the shares subject to the option vest on each monthly anniversary thereafter, subject to the Reporting Person's continuous service through each vesting date.

3. The option is immediately exercisable. 10% of the shares subject to the option vested on September 28, 2017, 15% of the shares subject to the option vested on September 28, 2018, and 1/48th of the shares subject to the option vest on each monthly anniversary thereafter, subject to the Reporting Person's continuous service through each vesting date.

4. 20% of the shares subject to the option vested and became exercisable on October 31, 2019 and 1/60th of the shares subject to the option vest and become exercisable on each monthly anniversary thereafter, subject to the Reporting Person's continuous service through each vesting date.

5. 25% of the shares subject to the option vested on October 24, 2020, and 1/48th of the shares subject to the option vest on each monthly anniversary thereafter, subject to the Reporting Person's continuous service through each vesting date.

6. Represents performance stock options granted to the reporting person on September 1, 2020, that vested and became exercisable on December 19, 2022 as a result of the reporting person having met the applicable performance criteria.

Remarks:

	/s/ Kendra Fox, as Attorney-in-Fact for Emily M. Leproust	10/06/2025
	** 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 transaction did Emily M. Leproust report on the Form 4 for TWST?

The filing reports a sell of 476 shares at $29.161 on 10/02/2025, executed to cover tax withholding related to vested restricted stock units.

Did the CEO make an optional sale of Twist Bioscience stock (TWST)?

No. The Form 4 states the sale was a mandatory "sell to cover" required by the company's equity plan to satisfy tax withholding, not a discretionary trade.

How many TWST shares does the reporting person own after the transaction?

The reporting person beneficially owned 632,560 shares of common stock following the reported transaction.

Are there any exercisable stock options disclosed for the reporting person?

Yes. The filing shows several employee stock options with various exercise prices; one performance option representing 64,950 shares vested and became exercisable on 12/19/2022, and some options are noted as immediately exercisable.

When was the Form 4 signed and filed?

The signature line shows the form was signed by an attorney-in-fact on 10/06/2025.