[Form 4] Standard BioTools Inc. Insider Trading Activity

Rhea-AI Filing Summary

Casdin-affiliated entities reported multiple open-market purchases of Standard BioTools Inc. (LAB) common stock between 08/13/2025 and 08/15/2025. The filings show aggregated acquisitions of at least 358,220 shares at weighted-average prices of approximately $1.21–$1.31, resulting in total beneficial ownership of 59,750,000 shares (held indirectly by the reporting entities) and certain direct holdings by Eli Casdin. The report also discloses a 2,901,062-share disposition directly by Eli Casdin and additional direct holdings of 13,939,637 and 2,744,219 shares by two Casdin funds. Eli Casdin is deputized to represent the reporting persons on LAB's board.

Positive

• Significant consolidated stake: Reporting persons collectively beneficially own 59,750,000 shares of LAB, indicating substantial economic exposure.
• Recent buying activity: Acquisitions of 358,220 shares across 08/13/2025–08/15/2025 at weighted-average prices of about $1.21–$1.31.

Negative

• None.

Insights

Securities Analyst

TL;DR Casdin entities increased net exposure to LAB through multiple purchases, consolidating a large indirect stake of 59.75 million shares.

The Form 4 details concentrated buying across three days (08/13/2025–08/15/2025) totaling 358,220 shares acquired at weighted-average prices between $1.2126 and $1.3104. Combined with existing holdings, the reporting group holds 59,750,000 shares indirectly, indicating a significant ownership position relative to the issuer. The filing also records a direct disposition of 2,901,062 shares by Eli Casdin and material direct holdings by two private funds. The deputization of Mr. Casdin to the board clarifies governance representation for these positions.

Corporate Governance Expert

TL;DR Multiple related entities filed jointly; Eli Casdin is the board representative, creating clear governance linkage to these holdings.

The Form 4 is filed by several affiliated reporting persons, each marked as directors or 10% owners where applicable, and states that Eli Casdin has been deputized to represent the reporting persons on the board. The filing includes clear attribution of direct versus indirect ownership across funds and the manager/adviser structure, and disclaims beneficial ownership beyond pecuniary interest. These disclosures align ownership and board representation for Section 16 purposes and clarify who exercises voting or dispositive power over the reported shares.

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
Estimated average burden
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)
08/13/2025

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	08/13/2025		P		75,000	A	$1.3104(1)	59,466,780	I	See footnote(2)
Common Stock	08/14/2025		P		133,220	A	$1.2126	59,600,000	I	See footnote(2)
Common Stock	08/15/2025		P		150,000	A	$1.2214(3)	59,750,000	I	See footnote(2)
Common Stock								2,901,062	D(4)
Common Stock								13,939,637	I	See footnote(5)
Common Stock								2,744,219	I	See footnote(6)

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 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)

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)

Explanation of Responses:

1. The price reported in Column 4 is a weighted average price. These shares were bought in multiple transactions within the range of $1.3075 to $1.3118. 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.

2. 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.

3. The price reported in Column 4 is a weighted average price. These shares were bought in multiple transactions within the range of $1.2179 to $1.2232. 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.

4. The securities are owned directly by Eli Casdin.

5. 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.

6. 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	08/15/2025
	/s/ Eli Casdin, Eli Casdin	08/15/2025
	Casdin Capital LLC, By: /s/ Eli Casdin, Managing Member	08/15/2025
	Casdin Partners GP LLC, By: /s/ Eli Casdin, Managing Member	08/15/2025
	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	08/15/2025
	Casdin Private Growth Equity Fund GP II, LLC, By: /s/ Eli Casdin, Managing Member	08/15/2025
	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	08/15/2025
	Casdin Private Growth Equity Fund GP, LLC, By: /s/ Eli Casdin, Managing Member	08/15/2025
	** 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 transactions did Casdin report for LAB on Form 4?

The Form 4 reports purchases of 75,000, 133,220, and 150,000 shares on 08/13/2025, 08/14/2025, and 08/15/2025, respectively, and a direct sale of 2,901,062 shares.

How many LAB shares do the reporting persons beneficially own after these transactions?

Following the reported transactions, the group beneficially owns 59,750,000 shares indirectly, with additional direct holdings disclosed for certain funds and Eli Casdin.

At what prices were the recent LAB purchases executed?

Reported weighted-average prices were approximately $1.3104 for 08/13/2025 and $1.2126–$1.2214 for purchases on 08/14–08/15/2025; footnotes state the purchases occurred within specified price ranges.

Which entities filed the Form 4 for LAB and how are they related?

Filers include Casdin Partners Master Fund, L.P.; Casdin Capital, LLC; Casdin Partners GP, LLC; Casdin Private Growth Equity Fund II, L.P.; Casdin Private Growth Equity Fund, L.P.; and related GP entities. Casdin Capital is the investment adviser and Eli Casdin is managing member.

Does the filing indicate any board representation related to these holdings?

Yes, the filing states that Eli Casdin has been deputized to represent the reporting persons on LAB's board.