Annexon Insider Purchase: 4,115 Shares Acquired Under 10b5-1 Plan

Rhea-AI Filing Summary

William H. Carson, a director of Annexon, Inc. (ANNX), purchased 4,115 shares of the company's common stock on 09/02/2025 at a weighted average price of $2.09 per share. The shares were bought under a Rule 10b5-1 trading plan adopted March 17, 2025, through multiple trades priced between $2.06 and $2.115.

Following the transaction, the reporting person beneficially owned 37,945 shares. The filing reports the purchase as a planned, rule-compliant acquisition rather than an opportunistic trade.

Positive

• Purchase executed under a Rule 10b5-1 trading plan, which indicates pre-scheduled, compliant insider trading
• Director increased beneficial ownership to 37,945 shares, aligning insider holdings with shareholder interests
• Price transparency provided: weighted average $2.09 and trade price range $2.06–$2.115 disclosed

Negative

• None.

Insights

Securities Analyst

TL;DR: Director bought a small block of stock under a 10b5-1 plan; increases insider stake modestly.

The 4,115-share purchase at a weighted average of $2.09 represents a routine, planned acquisition under a 10b5-1 program adopted March 17, 2025. The transaction increases the director's beneficial ownership to 37,945 shares. Given the size and the planned nature, the trade is unlikely to be materially price-moving or indicative of unexpected private information. Investors typically view 10b5-1 purchases as orderly and preplanned.

Corporate Governance Expert

TL;DR: Use of a 10b5-1 plan demonstrates governance compliance but limits real-time signaling value.

The filing clearly states the purchases were executed pursuant to a Rule 10b5-1 plan, which strengthens procedural compliance and reduces insider trading concerns. Because the trades were executed across a range of prices and under a pre-established plan, the information provides limited insight into management's current private view of corporate prospects. The disclosure is transparent and meets Section 16 reporting requirements.

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^*

Carson William H.

(Last) (First) (Middle)

C/O ANNEXON, INC.

1400 SIERRA POINT PKWY, BLDG C, STE 200

(Street)

BRISBANE CA 94005

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Annexon, Inc. [ ANNX ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
09/02/2025

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	09/02/2025		P(1)		4,115	A	$2.09(2)	37,945	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. The transactions reported herein were effected pursuant to the Reporting Person's Rule 10b5-1 trading plan, adopted March 17, 2025.

2. This transaction was executed in multiple trades in prices ranging from $2.06 to $2.115, inclusive. The price reported in Column 4 above reflects the weighted average purchase price. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares purchased at each respective price within the range set forth in this footnote.

	/s/ Jennifer Lew, Attorney-in-Fact	09/04/2025
	** 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 ANNX director William H. Carson report on Form 4?

He purchased 4,115 shares of Annexon common stock on 09/02/2025 under a Rule 10b5-1 plan.

At what price were the ANNX shares purchased according to the filing?

Weighted average price $2.09 per share; trades executed in a range from $2.06 to $2.115.

How many ANNX shares does the reporting person own after the purchase?

37,945 shares beneficially owned following the reported transaction.

Was the purchase part of a 10b5-1 plan for ANNX insider trades?

Yes. The Form 4 states the trades were effected pursuant to a Rule 10b5-1 trading plan adopted March 17, 2025.

Does this Form 4 indicate any sales or derivative transactions for ANNX?

No. The filing reports a non-derivative purchase of common stock and does not disclose derivative transactions or sales.