Nan Fung and Pivotal funds trim Bolt Biotherapeutics (BOLT) stake below 5%

Rhea-AI Filing Summary

Bolt Biotherapeutics, Inc. received an amended Schedule 13D showing updated ownership by Nan Fung- and Pivotal-affiliated entities in its common stock. Nan Fung Group Holdings Limited reports beneficial ownership of 87,486 shares, or 4.6% of the common stock, with other related entities holding smaller stakes.

The reported percentages are calculated using 1,919,441 outstanding shares of common stock, as referenced from the company’s Form 10-Q filed on November 12, 2025. The filing states that on February 26, 2026, the reporting persons ceased to be beneficial owners of more than five percent of Bolt’s common stock. In addition, Mr. Kam Chung Leung directly owns 8,684 shares of common stock.

Insights

Institutional ownership analyst

Large holder now reports a sub-5% stake in Bolt Biotherapeutics.

The amendment details how Nan Fung and Pivotal-affiliated entities currently hold various minority stakes in Bolt Biotherapeutics, with the largest reported position at 4.6% of the common stock. Percentages are based on 1,919,441 outstanding shares cited from a recent Form 10-Q.

A key point is that, as of February 26, 2026, the group no longer exceeds the 5% beneficial ownership threshold, which changes their regulatory reporting status. This shift may modestly broaden Bolt’s shareholder base, though the filing itself does not describe any specific transactions driving the change.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 4)

Bolt Biotherapeutics, Inc.

(Name of Issuer)

Common Stock, $0.00001 par value

(Title of Class of Securities)

097702203

(CUSIP Number)

Robert Hopfner
Pivotal bioVenture Partners Fund I UGP, 501 2nd Street, Suite 200
San Francisco, CA, 94107
(415) 697-1002

Louis Rambo
Proskauer Rose, LLP, 1001 Pennsylvania Avenue NW, Suite 600
Washington, DC, 20004-2533
(202) 416-6800

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

02/24/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

Nan Fung Group Holdings Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

VIRGIN ISLANDS, BRITISH

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 87,486.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 87,486.00

11

Aggregate amount beneficially owned by each reporting person

87,486.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

4.6 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

NF Investment Holdings Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

VIRGIN ISLANDS, BRITISH

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 87,486.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 87,486.00

11

Aggregate amount beneficially owned by each reporting person

87,486.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

4.6 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

Pivotal bioVenture Partners Fund I, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 52,556.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 52,556.00

11

Aggregate amount beneficially owned by each reporting person

52,556.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.7 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

Pivotal bioVenture Partners Fund I G.P., L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 52,556.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 52,556.00

11

Aggregate amount beneficially owned by each reporting person

52,556.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.7 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

Pivotal bioVenture Partners Fund I U.G.P. Ltd.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 52,556.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 52,556.00

11

Aggregate amount beneficially owned by each reporting person

52,556.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.7 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

Pivotal Partners Ltd

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 52,556.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 52,556.00

11

Aggregate amount beneficially owned by each reporting person

52,556.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.7 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

Pivotal Life Sciences Holdings Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 52,556.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 52,556.00

11

Aggregate amount beneficially owned by each reporting person

52,556.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.7 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

Nan Fung Life Sciences Holdings Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

VIRGIN ISLANDS, BRITISH

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 82,486.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 82,486.00

11

Aggregate amount beneficially owned by each reporting person

82,486.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

4.3 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

Permwell Management Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 5,000.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 5,000.00

11

Aggregate amount beneficially owned by each reporting person

5,000.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.3 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

NFLS Beta Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

VIRGIN ISLANDS, BRITISH

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 29,930.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 29,930.00

11

Aggregate amount beneficially owned by each reporting person

29,930.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.6 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 097702203

1

Name of reporting person

NFLS Platform Holdings Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 29,930.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 29,930.00

11

Aggregate amount beneficially owned by each reporting person

29,930.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.6 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, $0.00001 par value
(b)	Name of Issuer: Bolt Biotherapeutics, Inc.
(c)	Address of Issuer's Principal Executive Offices: 900 Chesapeake Drive, Redwood City, CALIFORNIA , 94063.
Item 5.	Interest in Securities of the Issuer
(a)	Items 5(a)-(c) and Item 5(e) of the Schedule 13D are amended and restated as follows: The information set forth in rows 11 and 13 of the cover pages to this Schedule 13D is incorporated by reference. The percentages set forth in row 13 are based on 1,919,441 outstanding shares of Common Stock, as reported by the Issuer in its Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 12, 2025. In addition, Mr. Kam Chung Leung directly owns 8,684 shares of Common Stock.
(b)	The information set forth in rows 7 through 10 of the cover pages to this Schedule 13D is incorporated by reference.
(c)	Except as set forth on Schedule A, which is incorporated into this Item 5(c) by reference, no Reporting Person has effected any transaction in shares of Common Stock in the past sixty days.
(e)	On February 26, 2026, the Reporting Persons ceased to be the beneficial owners of more than five percent of the Common Stock.

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.

Nan Fung Group Holdings Limited

Signature:	/s/ Tang Chun Wai Nelson
Name/Title:	Tang Chun Wai Nelson, Director
Date:	02/26/2026

NF Investment Holdings Limited

Signature:	/s/ Tang Chun Wai Nelson
Name/Title:	Tang Chun Wai Nelson, Director
Date:	02/26/2026

Pivotal bioVenture Partners Fund I, L.P.

Signature:	By Pivotal bioVenture Partners Fund I G.P., L.P.
Name/Title:	its General Partner
Date:	02/26/2026

Signature:	By Pivotal bioVenture Partners Fund I U.G.P., Ltd.
Name/Title:	its General Partner
Date:	02/26/2026

Signature:	/s/ Robert Hopfner
Name/Title:	Robert Hopfner, Authorized Signatory
Date:	02/26/2026

Pivotal bioVenture Partners Fund I G.P., L.P.

Signature:	By Pivotal bioVenture Partners Fund I U.G.P., Ltd.
Name/Title:	its General Partner
Date:	02/26/2026

Signature:	/s/ Robert Hopfner
Name/Title:	Robert Hopfner, Authorized Signatory
Date:	02/26/2026

Pivotal bioVenture Partners Fund I U.G.P. Ltd.

Signature:	/s/ Robert Hopfner
Name/Title:	Robert Hopfner, Authorized Signatory
Date:	02/26/2026

Pivotal Partners Ltd

Signature:	/s/ Sun Xintong
Name/Title:	Sun Xintong, Director
Date:	02/26/2026

Pivotal Life Sciences Holdings Limited

Signature:	/s/ Sun Xintong
Name/Title:	Sun Xintong, Director
Date:	02/26/2026

Nan Fung Life Sciences Holdings Limited

Signature:	/s/ Sun Xintong
Name/Title:	Sun Xintong, Director
Date:	02/26/2026

Permwell Management Limited

Signature:	/s/ Tang Chun Wai Nelson
Name/Title:	Tang Chun Wai Nelson, Director
Date:	02/26/2026

NFLS Beta Limited

Signature:	/s/ Sun Xintong
Name/Title:	Sun Xintong, Director
Date:	02/26/2026

NFLS Platform Holdings Limited

Signature:	/s/ Sun Xintong
Name/Title:	Sun Xintong, Director
Date:	02/26/2026

FAQ

What does the latest Schedule 13D/A report for Bolt Biotherapeutics (BOLT)?

The amended Schedule 13D reports updated holdings by Nan Fung and Pivotal-affiliated entities in Bolt Biotherapeutics common stock. It shows their largest reported position at 4.6% beneficial ownership and confirms they no longer own more than five percent as of February 26, 2026.

How many Bolt Biotherapeutics (BOLT) shares does Nan Fung Group Holdings Limited beneficially own?

Nan Fung Group Holdings Limited is reported to beneficially own 87,486 shares of Bolt Biotherapeutics common stock. This stake represents 4.6% of the class, based on 1,919,441 outstanding shares referenced from the company’s Form 10-Q filed on November 12, 2025.

What is Pivotal bioVenture Partners Fund I’s ownership in Bolt Biotherapeutics (BOLT)?

Pivotal bioVenture Partners Fund I, L.P. reports beneficial ownership of 52,556 shares of Bolt Biotherapeutics common stock. This position represents 2.7% of the class, according to the percentages calculated using 1,919,441 outstanding shares cited in the filing.

When did the reporting persons fall below 5% ownership of Bolt Biotherapeutics (BOLT)?

The filing states that the reporting persons ceased to be beneficial owners of more than five percent of Bolt Biotherapeutics common stock on February 26, 2026. This date marks when their collective reportable ownership dropped below the key regulatory disclosure threshold.

How many Bolt Biotherapeutics (BOLT) shares are used to calculate the ownership percentages?

All reported ownership percentages are based on 1,919,441 outstanding shares of Bolt Biotherapeutics common stock. This outstanding share figure comes from the company’s Form 10-Q filed with the Securities and Exchange Commission on November 12, 2025, as referenced in the amendment.

Does any individual associated with the reporting group directly own Bolt Biotherapeutics (BOLT) shares?

Yes. The amendment notes that Mr. Kam Chung Leung directly owns 8,684 shares of Bolt Biotherapeutics common stock. This direct holding is disclosed in addition to the various institutional and holding-company stakes reported by Nan Fung- and Pivotal-affiliated entities.