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For Upstream Bio, Inc., Decheng Capital Global Life Sciences Fund IV, L.P. reported beneficial ownership of 2,724,868 common shares as of September 30, 2026, or 4.98% of the class. The fund held the shares directly; its general partner, Decheng Capital Management IV (Cayman), LLC, and manager Xiangmin Cui reported shared voting and investment authority over the same shares. The percentage calculation used 54,771,041 shares outstanding as of August 4, 2026.
Key Figures
Beneficially owned common shares:2,724,868 sharesBeneficial ownership:4.98%Common shares outstanding:54,771,041 shares
3 metrics
Beneficially owned common shares2,724,868 sharesHeld directly by Decheng Capital Global Life Sciences Fund IV, L.P. as of September 30, 2026
Beneficial ownership4.98%Each reporting person as of September 30, 2026
Common shares outstanding54,771,041 sharesAs of August 4, 2026
Key Terms
beneficially owned, shared voting power, shared dispositive power
3 terms
beneficially ownedfinancial
"each Reporting Person beneficially owned 4.98% of the Issuer's common stock"
Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.
shared voting powerregulatory
"Shared Voting Power 2,724,868.00"
Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.
shared dispositive powerregulatory
"Shared Dispositive Power 2,724,868.00"
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
How many UPB shares did Decheng Capital report owning?
Decheng Capital Global Life Sciences Fund IV, L.P. directly held 2,724,868 Upstream Bio shares as of September 30, 2026. The fund, its general partner Decheng Capital Management IV (Cayman), LLC, and Xiangmin Cui each reported beneficial ownership of that same block.
Why do UPB's cover pages list ownership as 4.9%?
The cover-page percentages were rounded down to 4.9% because of EDGAR filing-system field limitations. The ownership disclosure states that each reporting person beneficially owned 4.98% as of September 30, 2026.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 2)
Upstream Bio, Inc.
(Name of Issuer)
Common Stock, par value $0.001 per share
(Title of Class of Securities)
91678A107
(CUSIP Number)
09/30/2026
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
91678A107
1
Names of Reporting Persons
Decheng Capital Global Life Sciences Fund IV, L.P.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
2,724,868.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,724,868.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,724,868.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
4.9 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
91678A107
1
Names of Reporting Persons
Decheng Capital Management IV (Cayman), LLC
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
2,724,868.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,724,868.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,724,868.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
4.9 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP Number(s):
91678A107
1
Names of Reporting Persons
Xiangmin Cui
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
2,724,868.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,724,868.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,724,868.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
4.9 %
12
Type of Reporting Person (See Instructions)
IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Upstream Bio, Inc.
(b)
Address of issuer's principal executive offices:
890 Winter Street, Suite 200, Waltham, MA, 02451.
Item 2.
(a)
Name of person filing:
The names of the persons filing this report (collectively, the "Reporting Persons") are:
Decheng Capital Global Life Sciences Fund IV, L.P. ("Fund IV")
Decheng Capital Management IV (Cayman), LLC ("GP IV")
Xiangmin Cui ("Dr. Cui")
The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G/A.
(b)
Address or principal business office or, if none, residence:
3000 Sand Hill Road, Building 2, Suite 110
Menlo Park, CA 94025
(c)
Citizenship:
Fund IV Cayman Islands
GP IV Cayman Islands
Dr. Cui United States
(d)
Title of class of securities:
Common Stock, par value $0.001 per share
(e)
CUSIP No.:
91678A107
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
Row 9 of each Reporting Person's cover page to this Schedule 13G/A sets forth the aggregate number of shares of common stock of the Issuer beneficially owned by such Reporting Person as of September 30, 2026 and is incorporated by reference.
The Reporting Persons' ownership of the Issuer's securities consists of 2,724,868 shares of common stock held directly by Fund IV. GP IV is the general partner of Fund IV and shares voting and investment authority over the shares held by Fund IV. Dr. Cui is the manager of GP IV. Dr. Cui shares voting and investment authority over the shares held by Fund IV.
(b)
Percent of class:
As of September 30, 2026, each Reporting Person beneficially owned 4.98% of the Issuer's common stock. Such percentage is based upon 54,771,041 shares of the Issuer's common stock outstanding as of August 4, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on August 11, 2026. Due to field limitations of the EDGAR filing system, the percentages listed in Row 11 of the Reporting Persons' cover pages have been rounded down to 4.9%.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
Row 5 of each Reporting Person's cover page to this Schedule 13G/A sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of September 30, 2026 and is incorporated by reference.
(ii) Shared power to vote or to direct the vote:
Row 6 of each Reporting Person's cover page to this Schedule 13G/A sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of September 30, 2026 and is incorporated by reference.
(iii) Sole power to dispose or to direct the disposition of:
Row 7 of each Reporting Person's cover page to this Schedule 13G/A sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of September 30, 2026 and is incorporated by reference.
(iv) Shared power to dispose or to direct the disposition of:
Row 8 of each Reporting Person's cover page to this Schedule 13G/A sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2026 and is incorporated by reference.
Item 5.
Ownership of 5 Percent or Less of a Class.
Ownership of 5 percent or less of a class
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
Not Applicable
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
Not Applicable
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
Decheng Capital Global Life Sciences Fund IV, L.P.
Signature:
/s/ Xiangmin Cui
Name/Title:
By Decheng Capital Management IV (Cayman), LLC, its General Partner, By Xiangmin Cui, Manager
