<SEC-DOCUMENT>0001193125-24-237580-index.html : 20241015
<SEC-HEADER>0001193125-24-237580.hdr.sgml : 20241015
<ACCEPTANCE-DATETIME>20241015160527
ACCESSION NUMBER:		0001193125-24-237580
CONFORMED SUBMISSION TYPE:	8-K
PUBLIC DOCUMENT COUNT:		3
CONFORMED PERIOD OF REPORT:	20241010
ITEM INFORMATION:		Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year
ITEM INFORMATION:		Financial Statements and Exhibits
FILED AS OF DATE:		20241015
DATE AS OF CHANGE:		20241015

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Upstream Bio, Inc.
		CENTRAL INDEX KEY:			0002022626
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		8-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42366
		FILM NUMBER:		241371879

	BUSINESS ADDRESS:	
		STREET 1:		890 WINTER STREET, SUITE 200
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		781-208-2466

	MAIL ADDRESS:	
		STREET 1:		890 WINTER STREET, SUITE 200
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
</SEC-HEADER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>d897785d8k.htm
<DESCRIPTION>8-K
<TEXT>
Document 1 - file: d897785d8k.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-3.1
<SEQUENCE>2
<FILENAME>d897785dex31.htm
<DESCRIPTION>EX-3.1
<TEXT>
Document 2 - file: d897785dex31.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-3.2
<SEQUENCE>3
<FILENAME>d897785dex32.htm
<DESCRIPTION>EX-3.2
<TEXT>
Document 3 - file: d897785dex32.htm

</DOCUMENT>
</SEC-DOCUMENT>