[Form 4] Standard BioTools Inc. Insider Trading Activity

Rhea-AI Filing Summary

Form 4 filings from multiple Casdin entities report insider purchases and a single disposition in Standard BioTools, Inc. (LAB). The Master Fund purchased 200,000 shares on 08/22/2025 at $1.2634 and 200,000 shares on 08/25/2025 at a weighted-average price reported as $1.2409 (range $1.2311–$1.2475). On 08/26/2025 the Master Fund bought 125,000 shares at $1.2635. Following these buys the Reporting Persons report beneficial ownership totals rising to as much as 60,275,000 shares (indirect). Separately, Eli Casdin directly disposed of 2,901,062 shares. Various Casdin funds and management entities are listed as reporting persons and Mr. Casdin is deputized to represent them on the issuer's board.

Positive

• Incremental purchases totaling 525,000 shares by the Master Fund across 08/22–08/26/2025 indicate added insider accumulation at prices near $1.24–$1.26
• Significant reported indirect beneficial ownership remains, with reported totals up to 60,275,000 shares following the transactions

Negative

• Direct disposition of 2,901,062 shares by Eli Casdin is reported, reducing his direct holding
• Form does not disclose motives, allocation of purchases among separate transactions, or the exact breakdown of the weighted-average trades without request

Insights

Financial Analyst

TL;DR: Multiple small purchases by Casdin entities and a notable direct sale by Eli Casdin were reported; position totals remain large.

The filings show incremental open-market purchases across three dates totaling 525,000 shares by the Master Fund at prices near $1.24–$1.26, increasing reported indirect beneficial ownership to reported totals up to 60,275,000 shares. Concurrently, a direct sale of 2,901,062 shares by Eli Casdin is reported. These are explicit changes in holdings; the filings do not provide motivations, timing beyond transaction dates, or proceeds. All figures are taken directly from the Form 4 entries and footnotes.

Corporate Governance Expert

TL;DR: Multiple reporting entities tied to the same manager filed jointly; Mr. Casdin is deputized as board representative.

The document lists several related reporting persons (Casdin Partners Master Fund, Casdin Capital, Casdin GP and multiple Casdin private funds) and states that Eli Casdin has been deputized to represent the Reporting Persons on the issuer's board. The filings include the required footnote disclaimers about beneficial ownership. These are routine governance disclosures present in the Form 4; the filing does not state any board actions or changes beyond deputization.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Casdin Partners Master Fund, L.P.

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS

SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

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)

3. Date of Earliest Transaction (Month/Day/Year)
08/22/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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, $0.001 par value per share	08/22/2025		P		200,000	A	$1.2634	59,950,000	I	See footnote(1)
Common Stock, $0.001 par value per share	08/25/2025		P		200,000	A	$1.2409(2)	60,150,000	I	See footnote(1)
Common Stock, $0.001 par value per share	08/26/2025		P		125,000	A	$1.2635	60,275,000	I	See footnote(1)
Common Stock, $0.001 par value per share								2,901,062	D(3)
Common Stock, $0.001 par value per share								13,939,637	I	See footnote(4)
Common Stock, $0.001 par value per share								2,744,219	I	See footnote(5)

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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

1. Name and Address of Reporting Person^*

Casdin Partners Master Fund, L.P.

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS

SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Casdin Capital, LLC

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS

SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Casdin Partners GP, LLC

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS

SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Casdin Private Growth Equity Fund II, L.P.

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS

SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Casdin Private Growth Equity Fund II GP, LLC

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS, SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Casdin Private Growth Equity Fund, L.P.

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS

SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

CASDIN PRIVATE GROWTH EQUITY FUND GP, LLC

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS

SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Casdin Eli

(Last) (First) (Middle)

1350 AVENUE OF THE AMERICAS

SUITE 2600

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. 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 ("Casdin"), the investment adviser to the Master Fund, (ii) Casdin Partners GP, LLC (the "GP"), the general partner of the Master Fund, and (iii) Eli Casdin, the managing member of Casdin and the GP.

2. The price reported in Column 4 is a weighted average price. These shares were bought in multiple transactions within the range of $1.2311 to $1.2475. The Reporting Persons undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares bought at each separate price within the range set forth in this footnote.

3. The securities are owned directly by Eli Casdin.

4. The securities are owned directly by Casdin Private Growth Equity Fund II, L.P. (the "Equity Fund II") and may be deemed to be indirectly beneficially owned by (i) Casdin, the investment adviser to the Equity Fund II, and (ii) Eli Casdin, the managing member of Casdin.

5. 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.

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. 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.

	Casdin Partners Master Fund, LP, By: Casdin Partners GP, LLC, its General Partner, By: /s/ Eli Casdin, Managing Member	08/26/2025
	Casdin Capital LLC, By: /s/ Eli Casdin, Managing Member	08/26/2025
	Casdin Partners GP LLC, By: /s/ Eli Casdin, Managing Member	08/26/2025
	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	08/26/2025
	Casdin Private Growth Equity Fund GP II, LLC, By: /s/ Eli Casdin, Managing Member	08/26/2025
	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	08/26/2025
	Casdin Private Growth Equity Fund GP, LLC, By: /s/ Eli Casdin, Managing Member	08/26/2025
	/s/ Eli Casdin, Eli Casdin	08/26/2025
	** Signature of Reporting Person	Date
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).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transactions were reported by Casdin for LAB in this Form 4?

The filings report purchases of 200,000 shares on 08/22/2025 at $1.2634, 200,000 shares on 08/25/2025 at a weighted-average $1.2409, and 125,000 shares on 08/26/2025 at $1.2635, and a direct sale of 2,901,062 shares by Eli Casdin.

How much beneficial ownership do the Reporting Persons claim after the transactions?

The Form reports indirect beneficial ownership amounts up to 60,275,000 shares after the reported purchases.

Which entities filed the Form 4 related to LAB?

Reporting persons include Casdin Partners Master Fund, L.P.; Casdin Capital, LLC; Casdin Partners GP, LLC; Casdin Private Growth Equity Fund II, L.P.; related GP entities and Eli Casdin.

Did the filing disclose how the weighted-average price was calculated?

Yes. Footnote (2) states the $1.2409 price is a weighted average of multiple transactions in the range $1.2311 to $1.2475, and the filer will provide a breakdown on request.

Is Eli Casdin on Standard BioTools' board according to the filing?

The filing states Eli Casdin has been deputized to represent the Reporting Persons on the board, and by virtue of that deputization they may be deemed directors for Section 16 purposes.

Are there any derivative securities reported in this Form 4?

No derivative securities are reported in Table II; the transactions listed are for common stock and a direct disposition.