Sera Prognostics CSO sells shares for tax withholding

Sera Prognostics Chief Scientific Officer John J. Boniface reported a mandated share sale to cover taxes on vesting RSUs.

Rhea-AI Filing Summary

Sera Prognostics Chief Scientific Officer John J. Boniface reported a mandated share sale to cover taxes on vesting RSUs. He sold 3,038 shares of Class A Common Stock at a weighted average price of $1.96 per share, in block trades between $1.87 and $2.03. The company required a “sell to cover” transaction for tax withholding, so this was not a discretionary trade. After the sale, he directly owned 147,359 shares.

Insider Trade Summary

Net Seller: 3,038 shares

Net Sell 1 txn

Insider Boniface John J.

Role Chief Scientific Officer

Sold 3,038 shs ($6K)

Type	Security	Shares	Price	Value
Sale	Class A Common Stock	3,038	$1.96	$6K

Holdings After Transaction: Class A Common Stock — 147,359 shares (Direct)

Footnotes (2)

1. F1. Represents the number of shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units ("RSUs"). The sale is mandated by the Issuer's election to require the satisfaction of tax withholding obligations to be funded by "sell to cover" transactions and does not represent a discretionary transaction by the Reporting Person.
2. F2. The price reported is a weighted average price. These shares were sold as part of a block trade in multiple transactions at prices ranging from $1.87 to $2.03, inclusive. The Reporting Person will provide to the staff of the Securities and Exchange Commission, the issuer, or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price with regard to the block trade.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did SERA Chief Scientific Officer John J. Boniface report in this Form 4?

John J. Boniface reported selling 3,038 SERA Class A Common shares. The sale was executed solely to cover tax withholding obligations triggered by the vesting of restricted stock units, under a company-mandated “sell to cover” arrangement, rather than a discretionary open-market decision.

How many SERA shares did the insider sell and at what price range?

He sold 3,038 shares at a weighted average price of $1.96. The transaction was a block trade executed in multiple parts, with individual sale prices ranging from $1.87 to $2.03 per share, as disclosed in the Form 4 footnote details.

Why were SERA shares sold by the Chief Scientific Officer in this filing?

The shares were sold to cover tax withholding obligations on vesting RSUs. The issuer requires these obligations to be satisfied via “sell to cover” transactions, meaning the sale was mandated by company policy and did not represent a voluntary trading decision by the officer.

How many SERA shares does John J. Boniface hold after this transaction?

Following the tax-related sale, he directly holds 147,359 shares of Sera Prognostics Class A Common Stock. This post-transaction ownership figure reflects his remaining equity position after selling 3,038 shares to satisfy withholding obligations tied to restricted stock unit vesting.

Was the SERA insider’s sale considered a discretionary open-market trade?

No, the sale was not discretionary. Although coded as an open-market sale, the footnote explains it was mandated under the issuer’s election to satisfy tax withholding via “sell to cover” transactions, so it does not reflect an independent trading choice by the insider.

Can investors obtain detailed pricing for the SERA insider’s block trade?

Yes. The filing states the reported price is a weighted average for trades between $1.87 and $2.03. The insider will provide full information on the number of shares sold at each separate price to regulators, the issuer, or any security holder upon request.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 03/10/2026 - 05:53 PM EDT Learn about SEC filing dates

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^*

Boniface John J.

(Last) (First) (Middle)

C/O SERA PROGNOSTICS, INC.

2749 EAST PARLEYS WAY, SUITE 200

(Street)

SALT LAKE CITY UT 84109

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
SERA PROGNOSTICS, INC. [ SERA ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

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

3. Date of Earliest Transaction (Month/Day/Year)
03/09/2026

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

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

X	Form filed by One Reporting Person
	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
Class A Common Stock	03/09/2026		S		3,038(1)	D	$1.96(2)	147,359	D

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

Explanation of Responses:

1. Represents the number of shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units ("RSUs"). The sale is mandated by the Issuer's election to require the satisfaction of tax withholding obligations to be funded by "sell to cover" transactions and does not represent a discretionary transaction by the Reporting Person.

2. The price reported is a weighted average price. These shares were sold as part of a block trade in multiple transactions at prices ranging from $1.87 to $2.03, inclusive. The Reporting Person will provide to the staff of the Securities and Exchange Commission, the issuer, or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price with regard to the block trade.

	/s/ Benjamin G. Jackson, Attorney-in-fact	03/10/2026
	** 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.