Sera Prognostics officer plans sale of 13,591 shares

Officer Austin Aerts filed to sell shares of SERA common stock primarily to cover tax withholding from restricted stock unit vesting under a mandated sell-to-cover arrangement.

Rhea-AI Filing Summary

Sera Prognostics, Inc. (SERA) received a Form 144 notice from officer Austin Aerts covering a planned sale of up to 13,591 shares of Class A Common Stock beginning on September 8, 2026. The shares relate to the vesting of restricted stock units and are being sold to fund tax withholding obligations through mandated sell-to-cover transactions, which the filing states are not discretionary.

Over the prior three months, Aerts reported additional sales of 5,440 shares on June 9, 2026 and 2,037 shares on June 11, 2026, also in Class A Common Stock.

Key Figures

Planned shares to be sold: 13,591 shares Shares sold June 9, 2026: 5,440 shares Shares sold June 11, 2026: 2,037 shares

3 metrics

Planned shares to be sold 13,591 shares Class A Common Stock planned for sale beginning September 8, 2026 under Form 144

Shares sold June 9, 2026 5,440 shares Class A Common Stock sold by Austin Aerts during the past three months

Shares sold June 11, 2026 2,037 shares Class A Common Stock sold by Austin Aerts during the past three months

Key Terms

Form 144, Rule 144, restricted stock units, sell to cover, +1 more

5 terms

Form 144 regulatory

"144: Filer Information"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

restricted stock units financial

"in connection with the vesting of restricted stock units."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

sell to cover financial

"to be funded by sell to cover transactions"

Sell to cover is when a person who receives company stock through options or awards sells just enough shares immediately to pay required taxes, exercise costs, or fees, keeping the rest. Think of it like cashing part of a bonus to cover the tax bill so you can keep the remainder. For investors, it can create predictable small selling pressure and slightly change the number of shares actually held by insiders without increasing long‑term dilution.

aggregate financial

"sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated"

A combined total or summary created by adding together multiple parts or data points. Used as a noun and a verb, it means pooling individual items (sales, revenues, assets, transactions, or data) into one overall figure so stakeholders can see the big picture; like pouring many small jars into a single container to measure the total amount. Aggregate figures matter to investors because they show the overall size, trend, or exposure of a business or market rather than the detail of each component.

FAQ

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

What does the Form 144 filing for SERA by Austin Aerts disclose?

The filing states that officer Austin Aerts plans to sell up to 13,591 shares of Sera Prognostics Class A Common Stock starting on September 8, 2026, in connection with the vesting of restricted stock units and related tax withholding obligations.

Why is Austin Aerts selling SERA shares under this Form 144?

According to the filing, the sale represents shares sold to cover tax withholding obligations tied to the vesting of restricted stock units. The sale is described as mandated by the issuer’s election to satisfy taxes through sell-to-cover transactions and is not a discretionary trade by Aerts.

How many SERA shares has Austin Aerts sold in the last three months?

The Form 144 reports prior sales of 5,440 shares of Class A Common Stock on June 9, 2026 and 2,037 shares on June 11, 2026, both attributed to Austin Aerts.

What class of SERA securities is covered by this Form 144 notice?

The notice covers Class A Common Stock of Sera Prognostics, Inc., listed on NASDAQ. The planned sale relates to shares underlying restricted stock units that vested on September 8, 2026.

Does the Form 144 indicate that the SERA stock sale is discretionary?

No. The remarks section specifies that the sale is mandated by the issuer’s election to fund tax withholding via sell-to-cover transactions and does not represent a discretionary transaction by the reporting person.

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

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Available on EDGAR 09/09/2026 - 04:07 PM EDT Accepted by SEC EDGAR 09/09/2026 - 04:05 PM EDT Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001979974
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Sera Prognostics, Inc.
SEC File Number	001-40606
Address of Issuer	2749 East Parleys Way Suite 200 Salt Lake City UTAH 84109
Phone	(801)-990-0520
Name of Person for Whose Account the Securities are To Be Sold	Aerts Austin
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Class A Common	Morgan Stanley Smith Barney LLC 1 New York Plaza 38th Floor New York NY 10004	13591	27195	39449466	09/08/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Class A Common	09/08/2026	Restricted Stock Unit Vesting	Issuer			13591	09/08/2026	Not Applicable

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Austin Aerts 2749 E. Parleys Way Suite 200 Salt Lake City UT 84109	Class A Common	06/09/2026	5440	11324
Austin Aerts 2749 E. Parleys Way Suite 200 Salt Lake City UT 84109	Class A Common	06/11/2026	2037	4085

144: Remarks and Signature

Remarks	The sale on this form represents the number of shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. 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.
Date of Notice	09/09/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Austin Aerts
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)