Was the Annexon (ANNX) director’s share purchase made under a Rule 10b5-1 plan?

Yes. A footnote states the transactions were effected under the reporting person’s Rule 10b5-1 trading plan adopted on December 8, 2025. Such plans pre-schedule trades, reducing the significance of short-term timing.

Annexon director buys 8,000 shares in open trade

Annexon, Inc. director William H. Carson bought 8,000 shares of common stock in an open-market transaction at $5.78 per share.

Filing Impact

(Neutral)

Filing Sentiment

(Positive)How Sentiment works

Sentiment and the balance of points

Rhea-AI Sentiment reads the wording of the document, how positive or negative its language is on a 1 to 5 scale. The balance of points shown with the takes weighs what the document actually discloses, so the two can disagree, for example when a trial that missed its main goal is described in upbeat language.

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Form Type

Rhea-AI Filing Summary

Annexon, Inc. director William H. Carson bought 8,000 shares of common stock in an open-market transaction at $5.78 per share. After this purchase, he directly holds 78,405 shares of Annexon stock. The filing notes the transaction was made under his pre-arranged Rule 10b5-1 trading plan, indicating it was scheduled in advance rather than timed discretionarily.

Insider Trade Summary 10b5-1

Net Buyer: 8,000 shares

Net Buy 1 txn

Insider Carson William H.

Role Director

Bought 8,000 shs ($46K)

Type	Security	Shares	Price	Value
Purchase	Common Stock	8,000	$5.78	$46K

Holdings After Transaction: Common Stock — 78,405 shares (Direct)

Footnotes (1)

F1. The transactions reported herein were effected pursuant to the Reporting Person's Rule 10b5-1 trading plan, adopted December 8, 2025.

Key Figures

Shares purchased: 8,000 shares Purchase price: $5.78 per share Shares owned after transaction: 78,405 shares +1 more

4 metrics

Shares purchased 8,000 shares Open-market buy on May 11, 2026

Purchase price $5.78 per share Common stock transaction

Shares owned after transaction 78,405 shares Director’s direct holdings post-purchase

Transaction type Open-market purchase (Code P) Non-derivative common stock

Key Terms

Rule 10b5-1 trading plan, open-market purchase, Form 4

3 terms

Rule 10b5-1 trading plan regulatory

"were effected pursuant to the Reporting Person's Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

open-market purchase financial

"transaction_action": "open-market purchase""

An open-market purchase is when an investor or a company buys shares on a public stock exchange at the going market price, rather than through a private deal. It matters to investors because these purchases change how many shares are available, can push the stock price up or signal confidence from large buyers, and often affect per-share metrics like earnings—think of it like someone buying lots of apples off a grocery shelf, reducing supply and potentially raising the price.

Form 4 regulatory

"INSIDER FILING DATA (Form 4)"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

FAQ

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

What did Annexon (ANNX) director William H. Carson do in this Form 4 filing?

Director William H. Carson reported buying 8,000 Annexon common shares in the open market at $5.78 each. This transaction increased his direct ownership to 78,405 shares, according to the Form 4 disclosure.

How many Annexon (ANNX) shares did the director purchase and at what price?

He purchased 8,000 shares of Annexon common stock at a price of $5.78 per share. This was an open-market transaction, as indicated by the Form 4 purchase code and description.

What is William H. Carson’s total Annexon (ANNX) shareholding after this transaction?

Following the reported purchase, William H. Carson directly owns 78,405 shares of Annexon common stock. This figure represents his direct holdings after adding the 8,000 shares bought in the open-market transaction.

Is this Annexon (ANNX) Form 4 transaction an open-market purchase or something else?

The transaction is an open-market purchase of common stock, coded “P” on the Form 4. That code and its description confirm it was a standard market buy, not an option exercise, gift, or tax-withholding event.

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

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Accepted by SEC EDGAR 05/13/2026 - 04:30 PM EDT

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^*

Carson William H.

(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. 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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/11/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	05/11/2026		P⁽¹⁾		8,000	A	$5.78	78,405	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. The transactions reported herein were effected pursuant to the Reporting Person's Rule 10b5-1 trading plan, adopted December 8, 2025.

	/s/ Jennifer Lew, Attorney-in-Fact	05/13/2026
	** 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)

Source: View Original Filing on SEC EDGAR