$SEPN

RA CAPITAL MANAGEMENT, L.P. (Kolchinsky Peter, Shah Rajeev M.) sold $63.5M of SEPN (indirect holdings)

RA CAPITAL MANAGEMENT, L.P. sold 1,493,000 indirectly-held shares of Septerna, Inc. (SEPN) at $42.50 ($63.45M total) across 2 trades on 2026-08-12. Filed jointly with RA Capital Healthcare Fund LP (Director), RA Capital Nexus Fund III, L.P. (Director), Kolchinsky Peter (Director) and Shah Rajeev M. (Director).

Original reporting
SEC EDGAR · RA CAPITAL MANAGEMENT, L.P., RA Capital Healthcare Fund LP, RA Capital Nexus Fund III, L.P., Kolchinsky Peter, Shah Rajeev M.
Published Aug 14, 2026, 9:11 PM UTC
Analysis
alphai AI DeskAI-generated
Added to alphai Aug 14, 2026, 9:36 PM UTC. Informational, not investment advice.
How this was made
alphai summarizes source reporting and applies a structured AI analysis for relevance, timing, sentiment and ticker impact. Always verify material claims with the original publisher.
alphai market briefInsider activity
Primary signal
$SEPN
Neutral
medium confidence
Mentioned
$SEPN
Relevance
8/10
alphai data visualization · based on SEC EDGAR
Decision brief

The 30-second read

$SEPNNeutralLow
01

Why it matters

The disclosed open-market sale reduces the disclosed holdings after the transaction and can influence near-term sentiment, but it does not provide new operational or financial guidance.

02

Market read

A sizable open-market sale by a 10% owner/director-related group is newly disclosed, creating modest sentiment risk for SEPN.

03

What to watch

No 10b5-1 plan is stated, but the filing also provides no rationale; traders should check for concurrent filings (other insiders, financing, trial updates) to avoid over-interpreting the sale.

Relevance 8/10Novelty 5/10Timing: filed 2026-08-14, sale executed 2026-08-12

Background

This is an SEC Form 4 insider transaction disclosure for Septerna, Inc. (SEPN) involving RA Capital Management and related directors.

Company-level read

Ticker impact

$SEPNNeutralMedium confidence
Context

Septerna (SEPN) disclosed a Form 4 showing RA Capital sold 1,493,000 shares at $42.50 on 2026-08-12 via indirect holdings.

Expected impact

Near-term sentiment risk, but likely limited fundamental signal without accompanying company news.

Evidence & confidence

The filing is a primary-source transaction detail with sizable notional value, but it lacks any stated reason, guidance change, or operational/regulatory catalyst.

Market effects

Minimal sector read-through; this is a single-company ownership transaction without broader biotech/sector policy or trial updates.

None indicated.

None indicated.

Counterpoint

Because the sale is by an indirect holder/10% owner and not explicitly tied to new negative company information, the market may discount it as routine portfolio management.

Key entities

  • Septerna, Inc.

    Company whose shares were sold; subject of the Form 4 disclosure.

  • RA Capital Management, L.P.

    10% owner/director-related reporting entity that sold shares via indirect holdings.

  • Kolchinsky Peter

    Co-reporting director listed on the joint filing.

  • Shah Rajeev M.

    Co-reporting director listed on the joint filing.

Full insider trading history

This story covers one filing. See everything behind it: every insider buy and sell on record, 10b5-1 plans, late filings, and which officers and directors are trading.

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