Twist Bioscience CEO sells 1,687 shares for taxes

The shares were sold to fund tax withholding on Restricted Stock Unit vesting, rather than through a discretionary trade.

Rhea-AI Filing Summary

Twist Bioscience Corp CEO and director Emily M. Leproust sold 1,687 common shares on September 21, 2026, at $165.4910 per share. The sale was a mandatory “sell to cover” transaction for tax withholding in connection with Restricted Stock Unit vesting, not a discretionary trade; no Rule 10b5-1 plan is reported. She directly held 618,902 common shares after the sale. The filing also lists options covering 131,290 shares at an exercise price of $23.3300 and 64,950 shares at $67.8500.

Insider Trade Summary

Net Seller: 1,687 shares

Net Sell 6 txns

Insider Leproust Emily M.

Role Chief Executive Officer

Sold 1,687 shs ($279K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1	1,687	$165.491	$279K
holding	Employee Stock Option (right to buy) F2	--	--	--
holding	Employee Stock Option (right to buy) F3	--	--	--
holding	Employee Stock Option (right to buy) F4	--	--	--
holding	Employee Stock Option (right to buy) F5	--	--	--
holding	Employee Stock Option (right to buy) F6	--	--	--

Holdings After Transaction: Common Stock — 618,902 shares (Direct); Employee Stock Option (right to buy) — 196,240 contracts (Direct)

Footnotes (6)

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.
2. F2. 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. F3. 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.
4. F4. 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.
5. F5. 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.
6. F6. The option is immediately exercisable. 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 vested and became exercisable on each monthly anniversary thereafter, subject to the Reporting Person's continuous service through each vesting date.

Key Figures

Common shares sold: 1,687 shares Sale price per share: $165.4910 per share Direct common shares after sale: 618,902 shares +2 more

5 metrics

Common shares sold 1,687 shares September 21, 2026

Sale price per share $165.4910 per share September 21, 2026

Direct common shares after sale 618,902 shares After the September 21, 2026 sale

Option underlying shares 131,290 common shares Exercise price $23.3300; expiration October 23, 2029

Option underlying shares 64,950 common shares Exercise price $67.8500; expiration August 31, 2030

Key Terms

sell to cover, Restricted Stock Units, performance stock options

3 terms

sell to cover financial

"funded by a “sell to cover” transaction"

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.

Restricted Stock Units financial

"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.

performance stock options financial

"Represents performance stock options granted to the reporting person"

FAQ

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

How many TWST shares did CEO Emily M. Leproust sell, and at what price?

Emily M. Leproust sold 1,687 common shares on September 21, 2026, at $165.4910 per share. The sale covered tax withholding associated with Restricted Stock Unit vesting and was not a discretionary trade.

What stock options did TWST CEO Emily M. Leproust report?

She reported options covering 131,290 common shares at an exercise price of $23.3300, expiring October 23, 2029, and options covering 64,950 common shares at $67.8500, expiring August 31, 2030.

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

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Available on EDGAR 09/23/2026 - 04:09 PM Accepted by SEC EDGAR 09/23/2026 - 04:07 PM 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^*

Leproust Emily M.

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/21/2026

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	09/21/2026		S		1,687(1)	D	$165.491	618,902	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)	$23.33							(3)	10/23/2029	Common Stock	131,290		131,290	D
Employee Stock Option (right to buy)	$67.85							12/19/2022	08/31/2030	Common Stock	64,950		64,950(4)	D
Employee Stock Option (right to buy)	$8.82							(5)	09/28/2027	Common Stock	0		0	D
Employee Stock Option (right to buy)	$26.66							(6)	11/18/2028	Common Stock	0		0	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. 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.

4. 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.

5. 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.

6. The option is immediately exercisable. 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 vested and became exercisable 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 Emily M. Leproust	09/23/2026
	** 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)