Annexon director Mark Blumenkranz files Form 3

Annexon, Inc. director Mark S. Blumenkranz filed an initial statement of beneficial ownership on Form 3.

Rhea-AI Filing Summary

Annexon, Inc. director Mark S. Blumenkranz filed an initial statement of beneficial ownership on Form 3. The filing identifies him as a director of Annexon but reports no transactions and no reportable holdings or derivative positions at this time. An Exhibit 24 power of attorney is referenced.

Key Terms

Form 3, beneficial ownership, Power of Attorney

3 terms

Form 3 regulatory

"filed an initial statement of beneficial ownership on Form 3"

Form 3 is the initial public filing that officers, directors and large shareholders must submit to report their ownership of a company’s securities when they become insiders. It acts like an opening inventory sheet that gives investors a starting point to see who holds significant stakes and to spot later trades or potential conflicts of interest, helping assess insider confidence and transparency.

beneficial ownership financial

"filed an initial statement of beneficial ownership on Form 3"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

Power of Attorney regulatory

"An Exhibit 24 power of attorney is referenced"

A power of attorney is a legal document that allows one person to make decisions and act on behalf of another person, often in financial or legal matters. It’s like giving someone a trusted helper or agent the authority to handle important tasks if you are unable to do so yourself. This matters to investors because it can impact how their assets are managed or transferred if they become unable to oversee their affairs.

FAQ

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

What does the Annexon (ANNX) Form 3 filed by Mark S. Blumenkranz disclose?

The Form 3 identifies Mark S. Blumenkranz as a director of Annexon, Inc. It reports no transactions and no reportable holdings or derivatives at the time of filing, and references an Exhibit 24 power of attorney.

Does the Annexon (ANNX) Form 3 show any stock transactions by Mark S. Blumenkranz?

No. The Form 3 for Annexon director Mark S. Blumenkranz lists no buy, sell, gift, or exercise transactions. All transaction counts and share totals in the structured data are zero for this filing.

Does Mark S. Blumenkranz report any Annexon (ANNX) share ownership on this Form 3?

The Form 3 shows no reportable holdings or derivative positions for Mark S. Blumenkranz. Holding entries and derivative summaries are both zero, indicating no ownership positions are reported in this filing.

What role does Mark S. Blumenkranz have at Annexon (ANNX) according to the Form 3?

The Form 3 states that Mark S. Blumenkranz is a director of Annexon, Inc. He is not reported as an officer or 10% owner in this filing; only his director status is indicated.

What is the Exhibit 24 mentioned in the Annexon (ANNX) Form 3 remarks?

The remarks reference Exhibit 24 - Power of Attorney. This typically authorizes another party to sign certain SEC documents on the reporting person’s behalf, but the exhibit’s detailed terms are not described in the structured data provided.

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

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Available on EDGAR 08/12/2026 - 06:09 PM Accepted by SEC EDGAR 08/12/2026 - 06:08 PM Learn about SEC filing dates

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Blumenkranz Mark S.

(Last) (First) (Middle)

C/O ANNEXON, INC.

1400 SIERRA POINT PKWY, BLDG C, STE 200

(Street)

BRISBANE CALIFORNIA 94005

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
08/10/2026

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

3a. Foreign Trading Symbol

5. If Amendment, Date of Original Filed (Month/Day/Year)

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

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

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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks:

Exhibit 24 - Power of Attorney

No securities are beneficially owned.

	/s/ Jennifer Lew, Attorney-in-Fact	08/12/2026
	** 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 5 (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 3: SEC 1473 (03-26)