Company · Ownership research

Upstream Bio, Inc. UPB

CIK 0002022626

Form 4 transactions dated Nov 1, 2023 to Nov 8, 2026, as reported to the SEC.

Insider trading Initial holdings Institutional holders

Insider filings on file run through Sep 17, 2026.

Some filings are submitted jointly by several insiders. The SEC form does not apportion the reported figures between them, so results include every joint filer.

Insider purchases & sales

Purchased: $48.02M
Sold: $104.80K

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

Insiders in this window

20243 of 3 preview events

Date	Insider	Activity	Trade value (USD)	% of prior holding
Oct 15, 2024	Blavatnik Len · Access Industries Holdings LLC · ACCESS INDUSTRIES MANAGEMENT, LLC · AI Biotechnology LLC · AI Upstream LLC 10% owner	Purchase	$19.98M 1,175,000 shares bought	Unavailable Direct holding	▾
Oct 15, 2024	Chimovits Erez Director · 10% owner	Purchase	$14.03M 825,000 shares bought	Unavailable Indirect holding	▾
Oct 15, 2024	ORBIMED ADVISORS LLC · OrbiMed Israel GP II, L.P. · OrbiMed Advisors Israel II Ltd · OrbiMed Capital GP VIII LLC Director · 10% owner	Purchase	$14.03M 825,000 shares bought	Unavailable Indirect holding	▾

Showing 3 / 3 record groups in 2024. The complete set is available through the API.

Upstream Bio, Inc. · UPB

Follow the people behind the trades.

Log in to look up the full history beyond 3 years, use advanced screening & filtering, download CSV, and reach other datasets through the Akkru API.

Download CSV
Earlier filings
Advanced screening & filtering
API & AI access

Already have an account?

＋ New accounts get free API credits to explore data beyond ownership filings.

For AI agents & developers

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 3 of 3 purchase / sale groups and 22 of 22 other groups; the totals and the monthly series cover the whole window.

Without an account: the last 3 years, with the row caps stated on the page. A free account opens all history on file on these pages and the CSV of what a page shows. Rows beyond the caps and bulk retrieval go through the authenticated API / MCP / CLI.

MCP  https://api.akkrudata.ai/mcp

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

Connect to MCP with OAuth and follow the returned pagination. Credits and usage limits depend on the account.

MCP endpoint: https://api.akkrudata.ai/mcp
API / MCP / CLI documentation: /documents
llms.txt: /llms.txt

Sources, coverage & how to read this data

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.