Sec Form 4 Filing - Casdin Partners Master Fund, L.P. @ STANDARD BIOTOOLS INC. - 2024-01-05

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Casdin Partners Master Fund, L.P. 2. Issuer Name and Ticker or Trading Symbol STANDARD BIOTOOLS INC. [ LAB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 1350 AVENUE OF THE AMERICAS, SUITE 2600 3. Date of Earliest Transaction (MM/DD/YY) 01/05/2024 (Street) NEW YORK, NY10019 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 01/05/2024 A 11,246,525 A 11,246,525 D ( 1 ) Common Stock 01/05/2024 A 2,744,219 A 2,744,219 I See footnote ( 2 ) Common Stock 1,200,000 I See footnote ( 3 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Casdin Partners Master Fund, L.P. 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Capital, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Partners GP, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Private Growth Equity Fund II, L.P. 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X Casdin Private Growth Equity Fund II GP, LLC 1350 AVENUE OF THE AMERICAS, SUITE 2600 X Casdin Private Growth Equity Fund, L.P. 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X CASDIN PRIVATE GROWTH EQUITY FUND GP, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X Casdin Partners FO1-MSV, LP C/O CASDIN PARTNERS GP, LLC 1350 AVENUE OF THE AMERICAS, SUITE 2600 NEW YORK, NY10019 X Signatures Casdin Partners Master Fund, LP By: Casdin Partners GP, LLC, its General Partner By: /s/ Eli Casdin, Managing Member 01/09/2024 Signature of Reporting Person Date Casdin Capital LLC By: /s/ Eli Casdin, Managing Member 01/09/2024 Signature of Reporting Person Date Casdin Partners GP LLC By: /s/ Eli Casdin, Managing Member 01/09/2024 Signature of Reporting Person Date Casdin Private Growth Equity Fund II, L.P. By: Casdin Private Growth Equity Fund II GP, LLC, its General Partner By: /s/ Eli Casdin, Managing Member 01/09/2024 Signature of Reporting Person Date Casdin Private Growth Equity Fund GP II, LLC By: /s/ Eli Casdin, Managing Member 01/09/2024 Signature of Reporting Person Date Casdin Private Growth Equity Fund, L.P., By: Casdin Private Growth Equity Fund II GP, LLC, its General Partner, By: /s/ Eli Casdin, Managing Member 01/09/2024 Signature of Reporting Person Date Casdin Private Growth Equity Fund GP, LLC, By: /s/ Eli Casdin, Managing Member, /s/ Eli Casdin, Eli Casdin 01/09/2024 Signature of Reporting Person Date Casdin Partners FO1-MSV, LP By: Casdin Partners GP, LLC, its General Partner By: /s/ Eli Casdin, Managing Member 01/09/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Received in exchange for 10,132,005 shares of common stock of SomaLogic, Inc. ("SomaLogic") pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated October 4, 2023, by and among Standard BioTools Inc. (the "Company"), Martis Merger Sub, Inc. and SomaLogic (the "Merger"). Per the terms of the Merger, each share of SomaLogic common stock was converted into the right to receive 1.11 shares of the Company's common stock (the "Exchange Ratio") at the effective time of the Merger (the "Effective Time"). The securities are owned directly by Casdin Partners Master Fund, L.P. (the "Master Fund") and may be deemed to be indirectly beneficially owned by (i) Casdin Capital, LLC, the investment adviser to the Master Fund ("Casdin"), (ii) Casdin Partners GP, LLC, the general partner of the Master Fund (the "GP"), and (iii) Eli Casdin, the managing member of Casdin and the GP. ( 2 )Received in exchange for 2,472,270 shares of common stock of SomaLogic pursuant to the Merger. Per the terms of the Merger, each share of SomaLogic common stock was converted pursuant to the Exchange Ratio at the Effective Time. The securities are owned directly by Casdin Private Growth Equity Fund, L.P. (the "Equity Fund") and may be deemed to be indirectly beneficially owned by (i) Casdin, the investment adviser to the Equity Fund, and (ii) Eli Casdin, the managing member of Casdin. ( 3 )The securities are owned directly by Casdin Partners FO1-MSV, LP ("Casdin FO1") and may be deemed to be indirectly beneficially owned by (i) Casdin, the investment adviser to Casdin FO1, (ii) the GP, the general partner of Casdin FO1, and (iii) Eli Casdin, the managing member of Casdin Capital, LLC and Casdin Partners GP, LLC.

Remarks: Eli Casdin has been deputized to represent the Reporting Persons on the board of directors of the Issuer. By virtue of Mr. Casdin's representation, for purposes of Section 16 of the Securities Exchange Act of 1934 (the "Exchange Act"), each of the Reporting Persons may be deemed directors by deputization of the Issuer. Mr. Casdin files separate Section 16 reports disclosing securities of the Issuer that he may be deemed to beneficially own for Section 16 purposes. Each Reporting Person disclaims beneficial ownership in the securities reported on this Form 4 except to the extent of its pecuniary interest, if any, therein, and this report shall not be deemed to be an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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