SER: Sio Capital reports 7.87% stake in Serina Therapeutics
Sio Capital Management reports 2,000,000 SER shares, 7.87% of class as of 9/30/2026, as an investment adviser filing.
What this filing says
Sio Capital Management, an investment adviser, reports beneficial ownership of 2,000,000 Serina Therapeutics common shares as of September 30, 2026, equal to 7.87% of the class. The holding is shared voting and dispositive power over shares held by affiliated funds on behalf of their investors. For a shareholder, this filing discloses a sizeable institutional holder rather than a company action.
Key figures
- Shares beneficially owned
- 2,000,000 shares
- Percent of class
- 7.87%
- Shares outstanding used for calculation
- 25,400,473 shares
- Date of event
- 09/30/2026
Written by Quantisnow AI from this filing. Not financial advice.
Key terms
- Schedule 13G:
- A short-form filing with the SEC by a holder of more than 5% of a public company's shares who is generally a passive investor.
- Beneficial ownership:
- Control over voting or selling shares, even if the shares are held in another person's name.
- Shared voting power:
- The ability to vote shares together with another party rather than alone.
- CUSIP:
- A nine-character identifier used to track individual securities, here 81751A108 for Serina common stock.
FAQ
How much of Serina Therapeutics does Sio Capital Management report owning?
The filing reports 2,000,000 shares, which it states is 7.87% of Serina's common stock as of September 30, 2026.
Who has voting power over the Serina shares in this filing?
Sio reports shared voting and dispositive power over the shares, which are held by affiliated funds for their investors, with Sio Capital's general partner and Michael Castor also disclaiming beneficial ownership.
Historical context for SER
Across the 24 sessions after earlier SER headlines, the stock closed higher 9 times and lower 15 times, with a median move of 3.1% in either direction. This shows timing only: many things move a stock in a session, and these figures do not show that any headline caused a move.
| Session | Earlier headline | SER | SPY |
|---|---|---|---|
| Sep 24, 2026 | Registration Is Now Open For Tribe Public’s CEO Presentation and Q&A Webinar Event "A New Approach to Advanced Parkinson’s Disease: Serina Discusses SER-252’s Clinical Progress" | -2.3% | -0.1% |
| Sep 11, 2026 | Serina Therapeutics to Present at the H.C. Wainwright 28th Annual Global Investment Conference | -11.2% | +0.9% |
| Sep 9, 2026 | Serina Therapeutics Reports Cohort 1 Observations from SER-252 Registrational Study in Advanced Parkinson’s Disease and Advances to Cohort 2 | +2.8% | -0.5% |
| Aug 14, 2026 | Serina Therapeutics Reports Second Quarter 2026 Financial Results and Provides Business Updates | -1.8% | -0.2% |
| Jul 24, 2026 | Serina Therapeutics to Participate in the BTIG Virtual Biotechnology Conference | -1.0% | +0.1% |
| Jul 23, 2026 | Serina Therapeutics Announces Completion of Enrollment and Dosing in Cohort 1 of Registrational Trial of SER-252 for Advanced Parkinson’s Diseaseand 1 other headline that session | -3.7% | -1.2% |
Keep researching SER
- What is Schedule 13G?A short-form SEC disclosure for investors who own more than 5% of a company's voting stock but hold it passively, without intent to influence control.
- Schedule 13D vs 13GSchedule 13D vs 13G explained: who must file when crossing 5% ownership, the 2024 deadlines, how activists differ from passive holders, and what Item 4 reveals.
- SER insider tradesEvery buy and sale reported by Serina Therapeutics Inc. officers, directors and large holders.
- SER financial statementsRevenue, profit, cash flow and balance sheet from Serina Therapeutics Inc.'s SEC filings.
- Market cap
- 30-day
- Sector
- Health Care
- Industry
- Biotechnology: Pharmaceutical Preparations
- Listed since
- 2018
Follow SER and get a push notification the moment its next story breaks.