Company · Ownership research

Upstream Bio, Inc. UPB

CIK 0002022626

Form 4 transactions dated Nov 1, 2023 to Nov 7, 2026, as reported to the SEC.

Insider trading Initial holdings Institutional holders

Insider filings on file run through Sep 17, 2026.

Insider purchases & sales

Purchased: $48.02M
Sold: $104.80K

Nov 1, 2023 – Sep 17, 2026
Available records · partial months are marked ·

202610 of 15 preview events

Date	Insider	Activity	Trade value (USD)	% of prior holding
Sep 16, 2026	Deykin Aaron Chief Medical Officer	Sale	$4.91K 895 shares sold	2.70% sold Direct holding	▾
Sep 16, 2026	Sutherland Everett Rand Chief Executive Officer · Director	Sale	$11.50K 2,095 shares sold	2.96% sold Direct holding	▾
Sep 16, 2026	Houghton Adam Chief Business Officer	Sale	$3.84K 700 shares sold	2.97% sold Direct holding	▾
Sep 16, 2026	GRAY MICHAEL CFO and COO	Sale	$4.68K 853 shares sold	2.96% sold Direct holding	▾
Sep 16, 2026	Ambrose Allison General Counsel	Sale	$2.66K 485 shares sold	3.02% sold Direct holding	▾
Jun 16, 2026	GRAY MICHAEL CFO and COO	Sale	$5.20K 853 shares sold	2.88% sold Direct holding	▾
Jun 16, 2026	Sutherland Everett Rand Chief Executive Officer · Director	Sale	$12.78K 2,095 shares sold	2.87% sold Direct holding	▾
Jun 16, 2026	Houghton Adam Chief Business Officer	Sale	$4.27K 700 shares sold	2.88% sold Direct holding	▾
Jun 16, 2026	Deykin Aaron Chief Medical Officer	Sale	$5.46K 895 shares sold	2.63% sold Direct holding	▾
Jun 16, 2026	Ambrose Allison General Counsel	Sale	$2.91K 477 shares sold	2.89% sold Direct holding	▾

Showing 15 / 15 record groups in 2026. The complete set is available through the API.

Upstream Bio, Inc. · UPB

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The initial HTML of this page carries its exact data as script#research-data (JSON): values, units, scope, preview limits and SEC sources. Read it directly, no script or API key needed; script#research-access says what needs an account. For the year shown, this page lists 15 of 15 purchase / sale groups and 16 of 16 other groups; the totals and the monthly series cover the whole window.

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{"action":"list","ticker":"UPB","transaction_code":["P","S"],"transaction_form_type":"4","page_size":20}

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Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.

Non-cancelled, non-derivative purchase (P) and sale (S) rows dated inside the public window, as reported. Share totals are on today's split-adjusted basis. Includes open-market and private transactions. Data after the latest filing is not asserted complete and is not zero-filled. A grouped event shares filing, transaction date, security, code, direction, ownership bucket and source. Derivative groups also match underlying security, exercise price, exercise/expiration dates and footnote references. Reported rows are retained; P/S price lots can be grouped. Post-transaction balances are never summed.