Sera Prognostics CSO sells 1,517 shares for taxes

Sera Prognostics Chief Scientific Officer John J. Boniface reported an open-market sale of 1,517 shares of Class A common stock at a weighted average price of $2.04 per share.

Rhea-AI Filing Summary

Sera Prognostics Chief Scientific Officer John J. Boniface reported an open-market sale of 1,517 shares of Class A common stock at a weighted average price of $2.04 per share. The sale was used to cover tax withholding obligations related to vesting restricted stock units and was mandated by the company’s sell-to-cover policy, not a discretionary trade. After the transaction, he directly holds 145,842 shares. The shares were sold in a block trade at prices ranging from $1.90 to $2.30 per share.

Insider Trade Summary

Net Seller: 1,517 shares

Net Sell 1 txn

Insider Boniface John J.

Role Chief Scientific Officer

Sold 1,517 shs ($3K)

Type	Security	Shares	Price	Value
Sale	Class A Common Stock	1,517	$2.04	$3K

Holdings After Transaction: Class A Common Stock — 145,842 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 $1.90 to $2.30, 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 insider transaction did SERA Chief Scientific Officer John J. Boniface report?

John J. Boniface reported selling 1,517 shares of SERA Class A common stock. The shares were sold in an open-market block trade to satisfy tax withholding from vesting restricted stock units under the company’s mandated sell-to-cover policy.

At what price were John J. Boniface’s SERA shares sold on March 11, 2026?

The reported weighted average sale price was $2.04 per share. According to the filing, the shares were sold in a block trade at prices ranging from $1.90 to $2.30, and detailed trade breakdowns are available on request.

Why did SERA’s Chief Scientific Officer sell 1,517 shares in this Form 4 filing?

The 1,517 shares were sold to cover tax withholding obligations from vesting RSUs. The issuer requires these obligations to be funded through sell-to-cover transactions, so the sale is characterized as non-discretionary for the reporting person.

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

Following the tax-related sale, John J. Boniface directly holds 145,842 shares of SERA Class A common stock. This post-transaction holding figure is disclosed in the Form 4 and reflects his remaining direct ownership position.

Does the SERA Form 4 indicate that the sale by John J. Boniface was discretionary?

The filing states the sale does not represent a discretionary transaction. It explains the issuer elected to require tax withholding obligations from vesting RSUs to be satisfied through mandated sell-to-cover transactions executed in the market.

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

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Accepted by SEC EDGAR 03/12/2026 - 08:12 PM 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)
03/11/2026

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	03/11/2026		S		1,517(1)	D	$2.04(2)	145,842	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 $1.90 to $2.30, 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	03/12/2026
	** 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.