Septerna Inc· SEPN

🇺🇸 US · SmallBroad USNASDAQ

Healthcare Biotechnology Website

Price: $39.50
Day: +2.76%
Mkt Cap: $1.78B
52W Range: $14.52 – $51.10
Volume: 241.5K
Beta: 2.29

D55D FrameworkQuarterly Data

Holdings Analysis

Insider activity, institutional flows, and fund ownership.

Smart Money: 3.1 / 5 (Neutral), from 3 of 3 components
Institutions Q2 2026: 166 institutions hold; 102 added, 32 reduced
Insiders Q3 2026: no purchases, 8 sales ($33.3M)

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Septerna Inc

SEPN|Healthcare|Biotechnology

Current price: $40

Smart Money

Dimension 5 of 5

Insider selling pace · Q3 2026

38x

vs own 6-quarter average

Seller breadth · Q3 2026

3 sellers

vs 1.5 avg per quarter

Institutional net breadth · Q2 2026

+104

153 adding vs 49 reducing

Institutional ownership · Q2 2026

N/A

overlapping 13F filings

Insider Selling Pace

Each quarter's selling vs this stock's own trailing 6-quarter average

Light <0.5xRoutineElevated >1.5xHeavy >3xBuying

Institutional Positions

Institutions adding above the line, reducing below, net as a line

NewIncreasedReducedClosedNet

Largest Institutional Holders, Q2 2026

By reported market value, and how each moved in the quarter

Holder

Change

RA CAPITAL MANAGEMENT, L.P.

7.0M

-0.6%

TRV GP V, LLC

6.2M

-0.6%

DRIEHAUS CAPITAL MANAGEMENT LLC

4.4M

+0.2%

TRV GP VI, LLC

4.2M

-0.6%

SAMSARA BIOCAPITAL, LLC

3.1M

-0.6%

GOLDMAN SACHS GROUP INC

3.1M

+4.7%

ETF & Fund Activity, Q2 2026

How the covering funds split between buying, holding and selling

48 buying32 unchanged28 selling

108 funds held SEPN in Q2 2026, holding 6.5M shares between them, up 10.8% on the quarter.

Largest fund holders

VANGUARD INDEX FUNDS1.2M sh

iSHARES TRUST1.1M sh

DRIEHAUS MUTUAL FUNDS576.1K sh

Notable Insider Transactions, Q3 2026

Largest open-market purchases and sales by value in the last eight quarters

Purchase · Oct 28

RA CAPITAL MANAGEMENT, L.P.

$68.9M

Sale · Aug 12

RA CAPITAL MANAGEMENT, L.P.

$31.7M

Purchase · Oct 28

Third Rock Ventures V, L.P.

$6.7M

Insider transactions from SEC Form 4 filings; institutional holdings from quarterly 13F filings, which are reported with a lag and can overlap between filers. 13F: quarterly institutional holdings report · ETF: Exchange-Traded Fund

See the complete picture

The full 5D Framework: Business Quality · Peer Comparison · Valuation · Analyst Sentiment · Smart Money

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Generated September 19, 2026

For educational purposes only. Not financial advice. Data may be delayed or incomplete.

Smart Money Sentiment

SEPN Smart Money Sentiment Score

A weighted 1-5 sentiment score across three smart money signals.

Smart Money

3.1/5

Neutral

Weighted across 3 components

Component Breakdown (3 of 3 available)

Insider Activity

40% weight

-100

Institutional Flow

50% weight

+84

Fund Flow

10% weight

+25

Overall Smart Money sentiment of 3.1/5 (Neutral) based on a weighted combination of 3 components. Insider activity uses a relative-baseline comparison against the stock's own history; institutional flow tracks position momentum and 13F share changes; fund flow measures ETF / mutual-fund buying vs selling. Higher scores indicate stronger bullish sentiment from professional investors.Last updated September 18, 2026.

Insider Trading Activity

Insider trading analysis comparing the latest quarter against the stock's own historical baseline.

Insider Selling Pace for SEPN

Each quarter's selling vs the stock's own trailing 6-quarter average; 1.0x is typical for this stock. Green triangles mark quarters with insider buying.

Very Bearish

Heavy insider selling in Q3 2026

8 sales totaling $33.3M (785.5K shares)

Share volume is 38x the historical average, extreme level

3 different insiders sold this quarter

Buying seen in 2 of 15 quarters

38x

Selling pace

vs own 6-qtr average

Heavy

4.82%

Stake sold

of active insiders' holdings

3 sellers

Seller breadth

vs 1.0 avg per quarter

Q1 2025

Last insider purchase

buying in 2 of 16 quarters

Notable Recent Transactions, SEPN

Top 8 highest-value insider trades from the last 8 quarters

RA CAPITAL MANAGEMENT, L.P.

10% Owner

Buy

3,828,400 shares at $18.00

≈69.3% of their stake after buying

Oct 28, 2024$68.91M

RA CAPITAL MANAGEMENT, L.P.

10% Owner

Sell

746,500 shares at $42.50

≈50.7% of their stake at the time

Aug 12, 2026$31.73M

Third Rock Ventures V, L.P.

10% Owner

Buy

370,500 shares at $18.00

≈6.0% of their stake after buying

Oct 28, 2024$6.67M

RA CAPITAL MANAGEMENT, L.P.

10% Owner

Buy

341,600 shares at $18.00

≈23.2% of their stake after buying

Oct 28, 2024$6.15M

Third Rock Ventures V, L.P.

10% Owner

Buy

279,500 shares at $18.00

≈8.9% of their stake after buying

Oct 28, 2024$5.03M

Third Rock Ventures VI, L.P.

10% Owner

Buy

612,674 shares at $5.92

≈16.3% of their stake after buying

Feb 20, 2025$3.63M

Third Rock Ventures VI, L.P.

10% Owner

Buy

427,668 shares at $5.94

≈10.2% of their stake after buying

Feb 21, 2025$2.54M

Shaikhly Samira

Chief People Officer

Sell

66,363 shares at $28.14

≈98.8% of their stake at the time

Mar 2, 2026$1.87M

Institutional Ownership Analysis

Institutional ownership analysis with position momentum, 13F share flow, and ownership percentage trends.

Institutional Positions for SEPN

Institutions adding (new + increased) above zero, reducing (reduced + closed) below, net as a line

New Increased Reduced Closed Net (adding − reducing)

Very Bullish

Institutions accumulating in Q2 2026

13F filings cover more than 100% of shares this quarter (overlapping reports), so ownership and share-flow figures are unreliable

Strong accumulation: 153 institutions adding vs 49 reducing positions

Momentum improving from prior quarter

+104

Net breadth

153 adding vs 49 reducing

Strong accumulation

3.12

Add / reduce ratio

in Q2 2026

+34

New − closed

51 initiated, 17 exited

4 of 10

Top holders adding

largest holders with a known change

Position Changes

Q2 2026: how are institutions adjusting their positions?

+153 growing-49 shrinkingNet: +104

102

New (51)

Increased (102)

Reduced (32)

Closed (17)

Top Institutional Holders, SEPN

Largest 8 institutional positions by ownership percentage as of Q2 2026

RA CAPITAL MANAGEMENT, L.P.

7.0M

$234.3M

Ownership

15.53%

-0.6%

TRV GP V, LLC

6.2M

$208.2M

Ownership

13.80%

-0.6%

DRIEHAUS CAPITAL MANAGEMENT LLC

4.4M

$148.5M

Ownership

9.84%

+0.2%

TRV GP VI, LLC

4.2M

$141.0M

Ownership

9.35%

-0.6%

SAMSARA BIOCAPITAL, LLC

3.1M

$105.5M

Ownership

6.99%

-0.6%

GOLDMAN SACHS GROUP INC

3.1M

$102.6M

Ownership

6.80%

+4.7%

BLACKROCK, INC.

1.9M

$64.7M

Ownership

4.29%

+5.4%

SIREN, L.L.C.

1.9M

$63.6M

Ownership

4.22%

-5.6%

ETF and Mutual Fund Holdings

ETF and mutual fund activity breakdown showing buying vs selling funds, top fund holders, and detailed holdings.

Fund Activity

Q2 2026: 108 ETFs and mutual funds reporting

48 buying28 sellingNet: +20

Buying (48)

Unchanged (32)

Selling (28)

In total, funds bought 1.2M shares and sold 444.1K this quarter. Each fund counts once in the bar above, whatever the size of its move.

Bullish Signal

Funds accumulating in Q2 2026

108 ETFs and mutual funds reporting

48 funds buying vs 28 selling

Top Fund Holders, SEPN

Largest 8 ETF and mutual fund positions by shares held, each fund's latest filing

VANGUARD INDEX FUNDS

1.2M

Weight

0.23%

Jun 30, 2026Increased

iSHARES TRUST

1.1M

Weight

0.00%

Jun 30, 2026Increased

DRIEHAUS MUTUAL FUNDS

576.1K

Weight

7.42%

Jun 30, 2026Increased

LOOMIS SAYLES FUNDS II

338.6K

Weight

0.02%

Jun 30, 2026Increased

SPDR SERIES TRUST

126.7K

Weight

0.00%

Jun 30, 2026Decreased

Bridge Builder Trust

10.0K

Weight

0.00%

Jun 30, 2026No change

PACIFIC SELECT FUND

8.6K

Weight

0.00%

Jun 30, 2026Decreased

MASTER INVESTMENT PORTFOLIO

7.7K

Weight

0.01%

Jun 30, 2026No change

Septerna Inc· SEPN

Holdings Analysis

Insider Trading Activity

1.3Transaction History43Real market purchases and sales onlyShow All Types

Institutional Ownership Analysis

2.4Detailed Holdings96Most recent institutional positions with changes and valuations

ETF and Mutual Fund Holdings

3.3Fund Holdings Details25Most recent ETF and mutual fund holdings with share counts and weights

Search stocks

Holdings Analysis

Insider Trading Activity

1.3Transaction History43Real market purchases and sales onlyShow All Types

Institutional Ownership Analysis

2.4Detailed Holdings96Most recent institutional positions with changes and valuations

ETF and Mutual Fund Holdings

3.3Fund Holdings Details25Most recent ETF and mutual fund holdings with share counts and weights