Upstream Bio, Inc. — Director's Dealing 2024

Oct 10, 2024

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Upstream Bio, Inc. (UPB)
CIK: 0002022626
Period of Report: 2024-10-10

Reporting Person: AI Upstream LLC (N/A)
Reporting Person: AI Biotechnology LLC (N/A)
Reporting Person: Access Industries Holdings LLC (N/A)
Reporting Person: ACCESS INDUSTRIES MANAGEMENT, LLC (N/A)
Reporting Person: Blavatnik Len (N/A)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Series A Preferred Stock	$		Common Stock (3000000)		Direct
Series B Preferred Stock	$		Common Stock (1117646)		Direct

Footnotes

F1: Each share of Series A preferred stock and Series B preferred stock (collectively, the "Preferred Stock") is currently convertible into Common Stock on a one-for-one basis at the option of the holder, but is expected to be convertible on a 1.049-for-one basis and to be converted automatically upon closing of the Issuer's initial public offering without payment of consideration. The Preferred Stock has no expiration date.

F2: The securities reported are held directly by AI Upstream LLC ("AI Upstream") and may be deemed to be beneficially owned by AI Biotechnology LLC ("AI Biotechnology"), Access Industries Holdings LLC ("AIH"), Access Industries Management, LLC ("AIM") and Len Blavatnik because (i) Mr. Blavatnik controls AIM and AIH, (ii) AIM controls AIH, (iii) AIH owns all of the voting units of AI Biotechnology and (iv) AI Biotechnology owns all of the voting units of AI Upstream. Each of the reporting persons (other than AI Upstream) disclaims beneficial ownership of these securities, except to the extent of its or his pecuniary interest therein, and this form shall not be construed as an admission that any such reporting person is the beneficial owner of any of the securities reported on this form.