Assembly Biosciences CEO sells shares to cover taxes

The sales funded tax withholding under a Compensation Committee administrative rule and were described as non-discretionary.

Available on EDGAR 11/03/2026 - 04:31 PM EST Accepted by SEC EDGAR 11/03/2026 - 04:30 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

Assembly Biosciences, Inc. CEO and President Jason A. Okazaki reported a 38,380-share performance-based restricted stock unit award, whose performance condition was achieved October 30, 2026. The award’s shares vest in two equal installments on October 30, 2026 and October 30, 2027, assuming continuous service on each date.

On November 2, 2026, he sold 6,133 shares at a weighted average of $19.6077 and 69 shares at a weighted average of $20.3480. The sales covered tax withholding related to restricted stock unit vesting and settlement under an administrative rule and were not discretionary.

Insider Trade Summary

Net Seller: 6,202 shares

Net Sell 3 txns

Insider Okazaki Jason A

Role CEO and President

Sold 6,202 shs ($122K)

Type	Security	Shares	Price	Value
Sale	Common Stock F2, F3	6,133	$19.6077	$120K
Sale	Common Stock F2, F4	69	$20.348	$1K
Grant/Award	Common Stock F1	38,380	$0.00	$0.00

Holdings After Transaction: Common Stock — 195,532 shares (Direct)

Footnotes (4)

1. F1. Represents shares of common stock issuable under a performance-based restricted stock unit award dated June 16, 2025. On October 30, 2026, the performance-based vesting condition was achieved. These shares of common stock vest in two equal installments, assuming continuous service on each vesting date, as follows: October 30, 2026 and October 30, 2027.
2. F2. The sales reported on this Form 4 represent shares sold by the reporting person to cover tax withholding obligations in connection with the vesting and settlement of restricted stock units. The sales are mandated by an administrative rule adopted by the Compensation Committee of the Issuer's Board of Directors that requires the satisfaction of tax withholding obligations to be funded by a "sell-to-cover" transaction and do not represent discretionary transactions by the reporting person.
3. F3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $19.28 to $20.27, inclusive. The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within.
4. F4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.30 to $20.37, inclusive. The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within.

Key Figures

Performance-based restricted stock unit award: 38,380 shares Shares sold: 6,133 shares Weighted average sale price: $19.6077 per share +2 more

5 metrics

Performance-based restricted stock unit award 38,380 shares Performance condition achieved October 30, 2026

Shares sold 6,133 shares November 2, 2026

Weighted average sale price $19.6077 per share 6,133 shares sold November 2, 2026

Shares sold 69 shares November 2, 2026

Weighted average sale price $20.3480 per share 69 shares sold November 2, 2026

Key Terms

performance-based restricted stock unit award, sell-to-cover, weighted average price

3 terms

performance-based restricted stock unit award financial

"performance-based restricted stock unit award dated June 16, 2025"

A performance-based restricted stock unit award is a promise to give company shares to an employee or executive only if the business hits specific targets over a set period. Think of it as a conditional prize that vests like a savings plan: if agreed goals (such as revenue, profit, or stock performance) are met, the recipient receives the shares; if not, they get nothing. Investors pay attention because these awards align management incentives with company results and can affect share count, future earnings and executive behavior.

sell-to-cover financial

"funded by a "sell-to-cover" transaction"

Sell-to-cover is when part of newly issued or exercised company stock is immediately sold to pay required taxes and fees, so the recipient keeps the remaining shares. For investors this matters because it reduces the number of shares insiders or employees actually hold after a grant, can create small, routine share sales that aren’t signal of cashing out, and slightly increases share supply on the market—like selling a portion of a paycheck to cover the tax bill.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

FAQ

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

How many ASMB shares did CEO and President Jason A. Okazaki sell?

Jason A. Okazaki sold 6,133 shares at a weighted average of $19.6077 and 69 shares at a weighted average of $20.3480 on November 2, 2026. The respective sale-price ranges were $19.28 to $20.27 and $20.30 to $20.37. The sales funded tax withholding under the Compensation Committee’s administrative sell-to-cover rule and were not discretionary; no Rule 10b5-1 plan is reported.

When do Jason A. Okazaki’s ASMB restricted stock unit shares vest?

The 38,380 shares under the performance-based restricted stock unit award vest in two equal installments on October 30, 2026 and October 30, 2027, assuming continuous service on each vesting date. The performance-based vesting condition was achieved on October 30, 2026.

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

Form 4 Insider Transactions: What Each Field Means →

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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^*

Okazaki Jason A

(Last) (First) (Middle)

C/O ASSEMBLY BIOSCIENCES, INC.

TWO TOWER PLACE, 7TH FLOOR

(Street)

SOUTH SAN FRANCISCO CALIFORNIA 94080

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
ASSEMBLY BIOSCIENCES, INC. [ ASMB ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/30/2026

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	10/30/2026		A		38,380(1)	A	$0	201,734	D
Common Stock	11/02/2026		S(2)		6,133	D	$19.6077(3)	195,601	D
Common Stock	11/02/2026		S(2)		69	D	$20.348(4)	195,532	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 shares of common stock issuable under a performance-based restricted stock unit award dated June 16, 2025. On October 30, 2026, the performance-based vesting condition was achieved. These shares of common stock vest in two equal installments, assuming continuous service on each vesting date, as follows: October 30, 2026 and October 30, 2027.

2. The sales reported on this Form 4 represent shares sold by the reporting person to cover tax withholding obligations in connection with the vesting and settlement of restricted stock units. The sales are mandated by an administrative rule adopted by the Compensation Committee of the Issuer's Board of Directors that requires the satisfaction of tax withholding obligations to be funded by a "sell-to-cover" transaction and do not represent discretionary transactions by the reporting person.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $19.28 to $20.27, inclusive. The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within.

4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.30 to $20.37, inclusive. The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within.

	/s/ John O. Gunderson, as Attorney-in-Fact	11/03/2026
	** 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)