[Form 4] Annexon, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Annexon, Inc. (ANNX) director reports sizable insider stock purchases. Over three consecutive days in November 2025, the reporting person, through Alerce Medical Technology Partners, L.P., bought 500,000 Annexon common shares on each of 11/17, 11/18, and 11/19.

The weighted average purchase prices were reported as $2.99, $3.18, and $3.94 for each respective day, with trades executed within stated price ranges. After these transactions, the reporting person beneficially owned 8,906,024 shares indirectly, including shares held in a revocable trust, various other trusts and entities, Satter Medical Technology Partners, L.P., and Alerce Medical, over which he has sole voting and dispositive power, subject to stated pecuniary interests.

Insights

Equity Ownership Analyst

Director, through affiliated funds and trusts, increased indirect ownership by 1.5M Annexon shares via open-market purchases over three consecutive days.

The filing shows a board member, acting through **Alerce Medical Technology Partners, L.P.**, buying **500,000** shares of **common stock** on each of 11/17/2025, 11/18/2025, and 11/19/2025. The weighted average purchase prices were $2.99, $3.18, and $3.94, respectively, with each trade executed across multiple price levels within disclosed ranges. After these transactions, the reporting person reports beneficial ownership of **8,906,024** shares, all held indirectly.

The ownership structure is spread across a revocable trust, other trusts and entities, **Satter Medical Technology Partners, L.P.**, and **Alerce Medical**, with the reporting person having sole voting and dispositive power over all such shares. The person formally disclaims beneficial ownership of many of these shares beyond their economic interest, which is typical when acting as trustee or manager. The key practical point is a sizable incremental open-market purchase by an existing director-affiliated holder, which increases the aggregate stake linked to this individual over a short period.

Items to monitor include any future Form 4 filings indicating whether this buying continues or reverses, as well as any parallel changes in filing status if ownership levels or roles shift. The execution ranges disclosed for each day’s trades may also matter for anyone analyzing trading liquidity around mid-November 2025. This filing is most relevant over the near to medium term as part of a pattern of insider-related ownership changes rather than a one-off administrative update.

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^*

Satter Muneer A

(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)
11/17/2025

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	11/17/2025		P		500,000(1)	A	$2.99(2)	7,906,024	I	See footnote(3)
Common Stock	11/18/2025		P		500,000(1)	A	$3.18(4)	8,406,024	I	See footnote(3)
Common Stock	11/19/2025		P		500,000(1)	A	$3.94(5)	8,906,024	I	See footnote(3)

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. All shares were purchased by Alerce Medical Technology Partners, L.P. ("Alerce Medical"). The Reporting Person has sole voting and dispositive power over the shares held by Alerce Medical. The Reporting Person disclaims beneficial ownership of the shares except to the extent of his pecuniary interest therein.

2. This transaction was executed in multiple trades in prices ranging from $2.695 to $3.115, 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.

3. As of November 19, 2025, includes (a) 240,000 shares that are held by the Muneer A. Satter Revocable Trust for which the Reporting Person serves as trustee and, in such capacity, has sole voting and dispositive power over all such shares, (b) 567,240 shares that are held by various other trusts and entities for which the Reporting Person serves as trustee, investment advisor or manager, as applicable, and, in each such capacity, has sole voting and dispositive power over all such shares, (c) 1,147,738 shares that are held by Satter Medical Technology Partners, L.P. for which the Reporting Person has sole voting and dispositive power over all such shares and (d) 6,951,046 shares that are held by Alerce Medical for which the Reporting Person has sole voting and dispositive power over all such shares. The Reporting Person disclaims beneficial ownership of all shares included under (b), (c) and (d) of this footnote, except to the extent of his pecuniary interest therein.

4. This transaction was executed in multiple trades in prices ranging from $3.01 to $3.285, 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.

5. This transaction was executed in multiple trades in prices ranging from $3.57 to $4.19, 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/ Muneer A. Satter	11/19/2025
	** 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).
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