Annexon, Inc. SEC Filings

Annexon, Inc. launched a primary offering of 25,096,153 shares of common stock and pre-funded warrants to purchase up to 3,750,000 shares, together with the shares issuable upon warrant exercise. The offering prices are $2.60 per share and $2.599 per pre-funded warrant, for gross proceeds of $74,996,247.80 and estimated net proceeds of about $69.9 million after fees and expenses.

The underwriters have a 30‑day option to buy up to 4,326,922 additional shares. Annexon plans to use proceeds to advance late‑stage programs, including tanruprubart in GBS and vonaprument in dry AMD with GA, and for working capital and general corporate purposes.

Pre-funded warrants have a $0.001 exercise price, do not expire, and include a 9.99% beneficial ownership limit (adjustable up to 19.99% with notice). Shares outstanding were 115,122,582 as of September 30, 2025, and are expected to be 140,218,735 immediately after this offering, assuming no exercise of pre-funded warrants.

Annexon, Inc. (ANNX) announced a primary offering of $75,000,000 of common stock, with the option for certain investors to purchase pre-funded warrants instead. The company also registered the shares issuable upon exercise of the pre-funded warrants. Underwriters have a 30‑day option to buy up to an additional $11,250,000 of common stock.

Pre-funded warrants will be sold at the share offering price minus $0.001 and have a $0.001 per share exercise price, are exercisable immediately, do not expire, and include a 9.99% Beneficial Ownership Limitation (adjustable up to 19.99% with 61 days’ notice). Annexon’s common stock trades on the Nasdaq Global Select Market under “ANNX”; the last reported sale price was $2.97 on November 11, 2025. Shares outstanding were 115,122,582 as of September 30, 2025; this is a baseline figure, not the amount being offered.

The company intends to use proceeds to advance its late‑stage neuroinflammation platform, led by global registrational programs tanruprubart in GBS and vonaprument in dry AMD with GA, and for working capital and other general corporate purposes. A 60‑day lock‑up applies, and sales under the existing 2024 ATM program are paused during this period.

Annexon, Inc. reported Q3 2025 results with a net loss of $54.9M and operating expenses of $57.0M, driven by research and development of $49.7M and general and administrative of $7.3M. Interest and other income was $2.1M. For the nine months, net loss was $158.4M as R&D spending rose with late‑stage programs.

Cash, cash equivalents and short‑term investments were $188.7M as of September 30, 2025 ($139.4M cash and equivalents; $49.3M short‑term investments). Management projects existing liquidity will fund operations for at least twelve months from the financial statement issuance date.

R&D increased as the company advanced tanruprubart (GBS) toward MAA/BLA packages and continued the vonaprument (GA) Phase 3 ARCHER II trial. The company raised $13.5M net via its 2024 ATM in Q3 and subsequently sold additional shares for $13.9M net after quarter‑end. Shares outstanding were 119,632,804 as of November 5, 2025; 38,543,577 shares are issuable upon exercise of pre‑funded warrants at $0.001 per share, subject to beneficial ownership limits.

Annexon, Inc. (ANNX) furnished an update on its business by announcing certain financial results for the third quarter ended September 30, 2025. The company provided these details in a press release titled “Annexon Reports Third Quarter 2025 Financial Results, Portfolio Progress and Key Anticipated Milestones,” attached as Exhibit 99.1.

The information was furnished under Item 2.02 of a Form 8‑K and, as stated, is not deemed “filed” for purposes of Section 18 of the Exchange Act and is not incorporated by reference unless specifically noted.

Annexon (ANNX) filed a Form 4 reporting an insider purchase by a director. On 10/30/2025, the director bought 4,115 shares of common stock at a $3.17 weighted average price, with individual trades executed between $3.15 and $3.20. The transaction was made under a Rule 10b5-1 trading plan adopted on March 17, 2025. Following the trade, the director beneficially owns 46,175 shares, held directly.

William H. Carson, a director of Annexon, Inc. (ANNX), purchased 4,115 shares of the company’s common stock on 09/30/2025 at a weighted average price of $3.05 per share under a Rule 10b5-1 trading plan adopted on March 17, 2025. After the reported purchase, the filing shows the reporting person beneficially owned 42,060 shares. The filing states the trades executed at prices ranging from $3.035 to $3.08, and the reporting person offers to provide details of the per-trade quantities on request. The transaction was reported on a Form 4 as required for Section 16 reporting.

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.

Annexon, Inc. is a clinical-stage biopharma with no approved products and significant historical losses. The company is advancing three lead programs: tanruprubart for Guillain-Barré Syndrome (GBS), which showed rapid and sustained functional improvement in a placebo-controlled Phase 3 trial and has Fast Track and orphan designations and a planned MAA submission in Europe in Q1 2026; vonaprument for geographic atrophy (GA), the only GA candidate to show significant vision preservation in Phase 2, with ARCHER II enrollment completed at 659 patients and topline data expected in H2 2026; and ANX1502, an oral C1s inhibitor with supportive Phase 1 PK/PD data and ongoing proof-of-concept study in cold agglutinin disease. The filing discloses recent equity offerings including pre-funded warrants (examples: 7,000,000 and 18,379,861 pre-funded warrants referenced) and ESPP availability of 2,959,996 shares. The company warns it will require substantial additional financing, relies on third-party manufacturers and collaborators, faces extensive regulatory and clinical risks, and has governance provisions that may limit stockholder control.

Annexon, Inc. Schedule 13G/A (Amendment No. 1) discloses that Logos Global entities and William Arsani filed jointly regarding Annexon common stock (CUSIP 03589W102) related to a reportable event dated 06/30/2025. The filing identifies five reporting persons: Logos Global Management LP, Logos Global Management GP LLC, Logos Global Master Fund LP, Logos GP LLC, and Arsani William, and provides the filer address at One Letterman Drive, Building C, Suite C3-350, San Francisco, CA 94129.

The statement states each reporting person beneficially owns 0 shares representing 0% of the class, with zero sole or shared voting or dispositive power. The reporting persons say they file jointly but disclaim membership in a group and disclaim beneficial ownership except to the extent of any pecuniary interest. The filing is signed by Arsani William on 08/13/2025.