Sec Form 3 Filing - CRITCHFIELD GREGORY C @ SERA PROGNOSTICS, INC. - 2021-07-14

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person CRITCHFIELD GREGORY C 2. Issuer Name and Ticker or Trading Symbol SERA PROGNOSTICS, INC. [ SERA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) C/O SERA PROGNOSTICS, INC., 2749 EAST PARLEYS WAY, SUITE 200 3. Date of Earliest Transaction (MM/DD/YY) 07/14/2021 (Street) SALT LAKE CITY, UT84109 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 79,140 D Class A Common Stock 630,832 I Held by The Gregory C. Critchfield & Trust ( 1 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 Series A-2 Preferred Stock $ 5.2 ( 4 ) ( 2 ) ( 3 ) Class A Common Stock 34,383 D Series B-1 Preferred Stock $ 5.2 ( 5 ) ( 2 ) ( 3 ) Class A Common Stock 5,253 D Series B-2 Preferred Stock $ 8.32 ( 6 ) ( 2 ) ( 3 ) Class A Common Stock 11,880 D Series C-1 Preferred Stock $ 12.37 ( 7 ) ( 2 ) ( 3 ) Class A Common Stock 4,727 D Series D Preferred Stock $ 9.02 ( 8 ) ( 2 ) ( 3 ) Class A Common Stock 28,730 D Stock Option (right to buy) $ 1.98 ( 9 ) 05/18/2027 Class A Common Stock 300,610 D Stock Option (right to buy) $ 1.77 ( 9 ) 02/27/2030 Class A Common Stock 462,338 D Stock Option (right to buy) $ 5.32 ( 9 ) 03/08/2031 Class A Common Stock 98,330 D Warrant (right to buy) $ 9.02 ( 10 ) 07/31/2029 Class A Common Stock 4,412 I Held by the Gregory C. Critchfield & Trust ( 1 ) Warrant (right to buy) $ 10.83 ( 10 ) 07/31/2029 Class A Common Stock 4,412 I Held by the Gregory C. Critchfield & Trust ( 1 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other CRITCHFIELD GREGORY C C/O SERA PROGNOSTICS, INC. 2749 EAST PARLEYS WAY, SUITE 200 SALT LAKE CITY, UT84109 X Chief Executive Officer Signatures /s/ Nishanti Dharia, Attorney-in-fact 07/14/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Dr. Critchfield is a Trustee of the Gregory C. Critchfield & Trust. Dr. Critchfield, in such capacity, may be deemed to indriectly beneficially own the securities owned by the trust except to the extent of his pecuniary interest therein, if any. ( 2 )The shares of preferred stock will automatically convert into the Issuer's Class A Common Stock in accordance with the Issuer's Restated Certificate of Incorporation, as amended, immediately upon completion of the Issuer's initial public offering. ( 3 )Not applicable ( 4 )The Issuer's Series A-2 Preferred Stock is convertible at the option of a holder at any time into shares of the Issuer's Class A Common Stock at a conversion price, as adjust ed to reflect the Issuer's recent 1-for-0.481 reverse stock split, of $5.20 per share. The Series A-2 Preferred Stock has no expiration date. ( 5 )The Issuer's Series B-1 Preferred Stock is convertible at the option of a holder at any time into shares of the Issuer's Class A Common Stock at a conversion price, as adjusted to reflect the Issuer's recent 1-for-0.481 reverse stock split, of $5.20 per share. The Series B-1 Preferred Stock has no expiration date. ( 6 )The Issuer's Series B-2 Preferred Stock is convertible at the option of a holder at any time into shares of the Issuer's Class A Common Stock at a conversion price, as adjusted to reflect the Issuer's recent 1-for-0.481 reverse stock split, of $8.32 per share. The Series B-2 Preferred Stock has no expiration date. ( 7 )The Issuer's Series C-1 Preferred Stock is convertible at the option of a holder at any time into shares of the Issuer's Class A Common Stock at a conversion price, as adjusted to reflect the Issuer's recent 1-for-0.481 reverse stock split, of $12.37 per share. The Series C-1 Preferred Stock has no expiration date. ( 8 )The Issuer's Series D Preferred Stock is convertible at the option of a holder at any time into shares of the Issuer's Class A Common Stock at a conversion price, as adjusted to reflect the Issuer's recent 1-for-0.481 reverse stock split, of $9.02 per share. The Series D Preferred Stock has no expiration date. ( 9 )These stock options vest over four years as follows: 1/48 of the original grant amount vests in monthly installments for four years following the grant date. ( 10 )Immediately exercisable.

Remarks: Exhibits 24.1 - Power of Attorney

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