Are insiders buying STRO stock?

Yes — 5 distinct insiders have bought STRO (SUTRO BIOPHARMA, INC.) on the open market, including 1 cluster buy where two or more insiders bought within a rolling window. The most recent qualifying activity was Oct 16, 2025.

How much STRO stock have insiders bought?

Insiders have bought a combined $89.6K of STRO across 5 open-market purchases, based on SEC Form 4 filings.

What is an insider cluster buy in STRO?

A cluster buy is two or more distinct SUTRO BIOPHARMA, INC. insiders — officers, directors, or 10% owners — each buying STRO on the open market within a rolling window. STRO has 1 detected cluster buy to date.

Where does this STRO insider trading data come from?

Every figure is parsed directly from SEC Form 4 filings on EDGAR, and each purchase on this page links back to its original filing document.

STRO insider buying

1 cluster buy

SUTRO BIOPHARMA, INC. · Healthcare

When two or more insiders at SUTRO BIOPHARMA, INC. buy STRO on the open market around the same time, that clustered conviction is one of the highest-signal patterns in SEC filing data. Below is every cluster we've detected in STRO plus the full record of qualifying open-market buys, each parsed directly from Form 4 filings and linked back to the source on SEC EDGAR.

Clusters

Distinct insiders

Total bought

$89.6K

Market cap

$507.6M

Detected clusters

Oct 15 – Oct 15, 2025
Detected Oct 15, 2025
High conviction5 insiders
Total bought
$89.6K
Market cap
$507.6M

All notable open-market buys in STRO

Every open-market Form 4 purchase, newest first. Click an insider to see their full buying record across companies.

Date	Insider	Shares	Price	Value	Filing
Oct 15, 2025	MATSUI CONNIEcluster Director	50,000	$0.80	$40.0K	SEC ↗
Oct 15, 2025	Chow Gregory K.cluster CFO	19,750	$0.81	$16.0K	SEC ↗
Oct 15, 2025	Gerber Hans-Petercluster CHIEF SCIENTIFIC OFFICER	17,000	$0.80	$13.6K	SEC ↗
Oct 15, 2025	Pauling Davidcluster Chief Admin. Ofcr. & GC	12,504	$0.80	$10.0K	SEC ↗
Oct 15, 2025	Chung Janecluster Director, Chief Executive Officer	12,500	$0.80	$10.0K	SEC ↗

More Healthcare stocks with insider cluster buys

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STRO insider buying — FAQ

Are insiders buying STRO stock?: Yes — 5 distinct insiders have bought STRO (SUTRO BIOPHARMA, INC.) on the open market, including 1 cluster buy where two or more insiders bought within a rolling window. The most recent qualifying activity was Oct 16, 2025.
How much STRO stock have insiders bought?: Insiders have bought a combined $89.6K of STRO across 5 open-market purchases, based on SEC Form 4 filings.
What is an insider cluster buy in STRO?: A cluster buy is two or more distinct SUTRO BIOPHARMA, INC. insiders — officers, directors, or 10% owners — each buying STRO on the open market within a rolling window. STRO has 1 detected cluster buy to date.
Where does this STRO insider trading data come from?: Every figure is parsed directly from SEC Form 4 filings on EDGAR, and each purchase on this page links back to its original filing document.

How we track insider buying in STRO

We continuously poll SEC EDGAR for new Form 4 filings and parse every open-market purchase (transaction code P). A cluster is recorded when two or more distinct insiders — officers, directors, or 10% owners — each buy STRO within a rolling window. We track clusters at every company size, from micro-caps to mega-caps. Every figure on this page traces back to an official filing; open any row to jump straight to the source document. What counts as a cluster buy?

This page is informational and reflects public filing data. It is not investment advice or a recommendation regarding STRO.