SERA · Sera Prognostics, Inc.

Each share is represented by a restricted stock unit ("RSU") granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by an additional RSU granted by the Board of Directors. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by a restricted stock unit ("RSU") granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These RSUs vest in three annual installments beginning with July 10, 2027, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by an additional RSU granted by the Board of Directors. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Consists of stock options granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by a restricted stock unit ("RSU") granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by an additional RSU granted by the Board of Directors. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Consists of stock options granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by an additional RSU granted by the Board of Directors. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by a restricted stock unit ("RSU") granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Consists of stock options granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Consists of stock options granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These stock options vest over three years as follows: 1/36 of the original grant amount vests in monthly installments for three years following the grant date, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by an additional RSU granted by the Board of Directors. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by a restricted stock unit ("RSU") granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Consists of stock options granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by an additional RSU granted by the Board of Directors. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by a restricted stock unit ("RSU") granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by a restricted stock unit ("RSU") granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by an additional RSU granted by the Board of Directors. These RSUs vest on the earlier of July 10, 2027 or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Consists of stock options granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

Consists of stock options granted pursuant to the issuer's Non-Employee Director Compensation Policy and its 2021 Equity Incentive Plan. These stock options vest over one year as follows: 1/12 of the original grant amount vests in monthly installments for one year following the grant date; provided, however, that the stock options shall be fully vested on the earlier of the first anniversary of the grant date or the date of the issuer's next Annual Meeting of Stockholders, subject to the Reporting Person continuing to provide services to the issuer.

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.

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 $2.12, 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.

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.

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 $2.12, 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.

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.

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 $2.12, 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.

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.

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 $2.12, 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.

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.

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 $2.12, 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.

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.

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 $1.96 to $2.21, 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.

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.

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 $1.96 to $2.21, 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.

The transaction(s) reported on this Form 4 was/were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 10, 2025.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $2.10 to $2.23, 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.

These shares were purchased pursuant to the Sera Prognostics, Inc. 2021 Employee Stock Purchase Plan ("ESPP"), for the purchase period of December 1, 2025 to May 29, 2026, and were exempt under both Rule 16b-3(d) and Rule 16b-3(c).

These shares were purchased pursuant to the Sera Prognostics, Inc. 2021 Employee Stock Purchase Plan ("ESPP"), for the purchase period of December 1, 2025 to May 29, 2026, and were exempt under both Rule 16b-3(d) and Rule 16b-3(c).

Each share is represented by a restricted stock unit ("RSU"). These RSUs vest over four years as follows: 1/16 of the original grant amount vests in quarterly installments for four years following the vesting commencement date, which is March 10, 2026, subject to the Reporting Person continuing to provide services to the issuer.

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 vesting commencement date, which is March 10, 2026, subject to the Reporting Person continuing to provide services to the issuer.

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 vesting commencement date, which is March 10, 2026, subject to the Reporting Person continuing to provide services to the issuer.

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 vesting commencement date, which is March 10, 2026, subject to the Reporting Person continuing to provide services to the issuer.

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 vesting commencement date, which is March 10, 2026, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by a restricted stock unit ("RSU"). These RSUs vest over four years as follows: 1/16 of the original grant amount vests in quarterly installments for four years following the vesting commencement date, which is March 10, 2026, subject to the Reporting Person continuing to provide services to the issuer.

Each share is represented by a restricted stock unit ("RSU"). These RSUs vest over four years as follows: 1/16 of the original grant amount vests in quarterly installments for four years following the vesting commencement date, which is March 10, 2026, subject to the Reporting Person continuing to provide services to the issuer.