Septerna, Inc.: 5%+ holders

As of November 6, 2026, 2 holders' latest Schedule 13D or 13G filings report owning 5% or more of Septerna, Inc. The largest reported stake is RA Capital Management, L.P.'s, at 11.8%. 3 filings are on record since February 17, 2026 (Schedule 13D/A, August 14, 2026).

DRIEHAUS CAPITAL MANAGEMENT LLC also filed stake reports on 16 other companies ↓

Sell to companies like Septerna, Inc? Enter your website and see 10 with a filed reason to buy from you this month. Free.

Your website Find my buyers

Opens in a new tab. No signup.

Key facts

• Filing 2026-08-14 · Reporting person: RA Capital Management, L.P. · Sole voting: 0 · Shared voting: 5,525,324 · Sole dispositive: 0 · Shared dispositive: 5,525,324 · SCHEDULE 13D/A, 2026-08-14
• Filing 2026-08-14 · Reporting person: Driehaus Capital Management LLC · Sole voting: 0 · Shared voting: 4,433,058 · Sole dispositive: 0 · Shared dispositive: 4,433,058 · SCHEDULE 13G/A, 2026-08-14
• Filing 2026-02-17 · Reporting person: Biotechnology Value Fund L P · Sole voting: 0 · Shared voting: 919,814 · Sole dispositive: 0 · Shared dispositive: 919,814 · SCHEDULE 13G/A, 2026-02-17

Septerna, Inc. has 3 Schedule 13D or 13G filings on record since 2026-02-17. 2 holders' latest filing reports 5% or more of common stock, par value $0.001 per share. Each figure below is the holder's own, as filed, with the filing linked.

Holders

Swipe the table sideways to see every column.

Holding shares or following this stake? See who's behind Septerna, Inc. and the warning signs.

See Septerna, Inc.'s free Snapshot Watch Septerna, Inc.: email me the next time it files something

Free to see. No signup.

Keep reading

More on Septerna, Inc. and the records around it.

Septerna, Inc. elsewhere on the record

• IPO filing Oct 2024
• Who owns it

Companies that share a holder

• DRIEHAUS CAPITAL MANAGEMENT LLC also filed stake reports on 16 other companies: Cardinal Infrastructure Group Inc. (Aug 2026), Cue Biopharma, Inc. (Aug 2026), Definium Therapeutics, Inc. (Aug 2026)
• BIOTECHNOLOGY VALUE FUND L P also filed stake reports on 55 other companies: Frazier Life Sciences Acquisition Corp. II (Oct 2026), Olema Pharmaceuticals, Inc. (Oct 2026), Foghorn Therapeutics Inc. (Oct 2026)
• RA Capital Management, L.P. also filed stake reports on 100 other companies: Climb Bio, Inc. (Nov 2026), Bambusa Therapeutics, Inc. (Nov 2026), SOLID BIOSCIENCES INC. (Nov 2026)

Want the whole picture on Septerna, Inc.?

Example from a real report (our sample on Target): “Target eliminated approximately 1,800 corporate positions, with around 1,000 employees receiving layoff notices and the remainder accounted for by eliminating open roles.” Source: NBC News

A Full Report on Septerna, Inc.: verified, sourced, every claim cited, ready in a few minutes. See pricing.

What the Full Report on Septerna, Inc. covers

1. The Short Answer

2. Which Company This Is

3. What They Do, And How The Money Works

4. Who Runs It, And How To Reach Them

5. The Money: Funding, Valuation, Runway

6. Who Pays Them, And Who They Are Up Against

7. Warning Bells

8. Sources

   7 cited sources found

Plus the sections for what you are deciding, which you pick after ordering.

Order Full ReportSee a sample report

A real finished report, first screen. Opens in a new tab.

Voting and dispositive power, as filed

Swipe the table sideways to see every column.

The latest filing identifies Septerna, Inc. by CUSIP 81734D104 and gives its principal executive office as 250 East Grand Avenue, South San Francisco, CA 94080 (SCHEDULE 13D/A, 2026-08-14).

What the percentages are based on

The following percentages are based on 44,774,192 Shares outstanding as of November 4, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 10, 2025.Bvf Partners L P, SCHEDULE 13G/A, 2026-02-17

Timeline

Swipe the table sideways to see every column.

Questions about who owns Septerna, Inc.

Who owns Septerna, Inc.?

On this page, 2 holders' latest ownership filings report 5% or more of Septerna, Inc.: RA Capital Management, L.P. (11.8%, Schedule 13D/A, filed 2026-08-14) and Driehaus Capital Management LLC (9.83%, Schedule 13G/A, filed 2026-08-14).

Who are the largest shareholders of Septerna, Inc.?

By the share each holder's latest filing reports, the largest holders of Septerna, Inc. on this page are RA Capital Management, L.P. (11.8%) and Driehaus Capital Management LLC (9.83%).

When did RA Capital Management, L.P. buy into Septerna, Inc.?

The filings give report dates, not purchase dates. The earliest filing from RA Capital Management, L.P. on this page is the Schedule 13D/A, filed 2026-08-14, reporting 11.8%. That earliest filing is itself an amendment, which updates an earlier report.

Is this an audit or a full list?

Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 3 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.

Also on the record for Septerna, Inc.

Swipe the table sideways to see every column.

Tools for this story

Each opens in a new tab, filled in for Septerna, Inc.. With no account yet, you sign up free and land on the result.

• Get an alert when Septerna, Inc. is mentioned again
• Find former Septerna, Inc. employees to interview
• Verify a claim or statistic

Where this comes from

Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.

Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.

All recent stakesThat week's stakes