<SEC-DOCUMENT>0000950123-24-006650-index.html : 20241108
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ACCESSION NUMBER:		0000950123-24-006650
CONFORMED SUBMISSION TYPE:	DRSLTR
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20240718

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:		DRSLTR

	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
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Document 1 - file: filename1.htm

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Document 2 - file: g865177g0716080431851.jpg

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