SCHEDULE: AnaptysBio: Sirenia Capital Management Discloses 6.7% Stake
Beneficial Ownership Filing
Sirenia Capital Management LP and Alex Silverstein have jointly filed a Schedule 13G, disclosing beneficial ownership of 6.7% of AnaptysBio, Inc. common stock as of March 31, 2026.
Summary
- Sirenia Capital Management LP and Alex Silverstein have jointly reported their beneficial ownership of AnaptysBio, Inc. common stock.
- As of March 31, 2026, the reporting persons collectively beneficially own 1,920,402 shares of AnaptysBio's common stock.
- This represents 6.7% of the total outstanding shares, based on the company's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which stated 28,748,255 shares outstanding as of February 27, 2026.
- Sirenia Capital Management LP manages the investment fund and accounts holding these shares.
- Alex Silverstein is the managing member of the general partner of Sirenia Capital Management LP.
- The filing is made under Rule 13d-1(k) of the Securities Exchange Act of 1934, indicating a joint filing agreement between the parties.
- Both reporting persons are classified as Investment Advisers (IA) and Investment Companies (IN) or Holding Companies (HC) respectively.
Sentiment
Score: 5
Explanation: StockSavvy.ai views this as a neutral filing, as it represents a standard regulatory disclosure of beneficial ownership rather than an announcement of new financial performance or strategic initiatives.
Positives
- Disclosure of a significant ownership stake (6.7%) by Sirenia Capital Management LP and Alex Silverstein in AnaptysBio, Inc.
- The filing indicates a structured and compliant approach to reporting beneficial ownership through a joint filing agreement.
Risks
- While this filing is a standard disclosure, significant changes in beneficial ownership can sometimes precede activist investor actions or strategic shifts, which could introduce uncertainty.
Future Outlook
This filing is a disclosure of current beneficial ownership and does not contain forward-looking statements or guidance from AnaptysBio, Inc.
Industry Context
StockSavvy.ai notes that Schedule 13G filings are routine disclosures for institutional investors crossing certain ownership thresholds. The 6.7% stake by Sirenia Capital Management LP in AnaptysBio, Inc. places them as a significant shareholder, which could be relevant in the biotechnology sector where substantial stakes can sometimes precede strategic discussions or influence corporate actions.
Stakeholder Impact
- Shareholders: The disclosure of a significant stake by an institutional investor may be viewed positively, indicating confidence in the company's prospects, or neutrally as a routine filing.
- Management: The company's management will be aware of Sirenia Capital Management LP's significant ownership, which could influence future strategic decisions or communications.
Next Steps
- Monitor future filings from Sirenia Capital Management LP and Alex Silverstein for any changes in their beneficial ownership of AnaptysBio, Inc.
- Observe any potential strategic actions or communications from Sirenia Capital Management LP regarding their investment in AnaptysBio, Inc.
Key Dates
| Date | Description |
|---|---|
| 02/27/2026 | Date as of which AnaptysBio, Inc. reported 28,748,255 shares of Common Stock outstanding in its Annual Report on Form 10-K. |
| 03/03/2026 | Date AnaptysBio, Inc. filed its Annual Report on Form 10-K for the fiscal year ended December 31, 2025. |
| 03/31/2026 | Date of Event Which Requires Filing of this Statement (Schedule 13G). |
| 05/15/2026 | Date of filing for the Schedule 13G and Joint Acquisition Statement. |
Keywords
AnaptysBio, Schedule 13G, Sirenia Capital Management LP, Alex Silverstein, Beneficial Ownership, SEC Filing, Investment Management, Common Stock, 6.7% Stake
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