Filing Details

The remainder of this cover page shall be filled out for a reporting persons initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

CUSIP No. 78472W104

   NAMES OF REPORTING PERSONS

  Polaris Management Co. VII, L.L.C.

  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions)

  (a)  ☐        (b)  ☒

  SEC USE ONLY

  SOURCE OF FUNDS (see instructions)

  AF

  CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) or 2(e)

  ☐

  CITIZENSHIP OR PLACE OF ORGANIZATION

  Delaware

NUMBER OF

SHARES

 BENEFICIALLY 

OWNED BY

EACH

REPORTING

PERSON

WITH

  SOLE VOTING POWER

  0

  SHARED VOTING POWER

  2,727,648 (1)

  SOLE DISPOSITIVE POWER

  0

  SHARED DISPOSITIVE POWER

  2,727,648 (1)

  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

  2,727,648 (1)

  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (see instructions)

  ☐

  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

  9.7% (2)

  TYPE OF REPORTING PERSON (see instructions)

  OO

Consists of (i) 2,549,307 shares held of record by PP VII (as defined in Item 2(a) below) and (ii) 178,341 shares held of record by PPE VII (as defined in Item 2(a) below). PMC VII (as defined in Item 2(a) below) is the general partner of each of PP VII and PPE VII and may be deemed to have voting, investment and dispositive power with respect to these securities. The Managing Members (as defined in Item 2(a) below) are the managing members of PMC VII. Ms. Schulman (as defined in Item 2(a) below), a member of the Issuers board of directors, holds an interest in PMC VII. Each of the Managing Members and Ms. Schulman may be deemed to share voting, investment and dispositive power with respect to these securities.

Based on 28,066,795 shares of the Issuers Common Stock outstanding as of November 3, 2021, as reported on the Issuers Quarterly Report on Form 10-Q, for the quarter ended September 30, 2021, as filed with the United States Securities and Exchange Commission (the Commission) on November 10, 2021 (the Form 10-Q).

CUSIP No. 78472W104

   NAMES OF REPORTING PERSONS

  Polaris Partners VII, L.P.

  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions)

  (a)  ☐        (b)  ☒

  SEC USE ONLY

  SOURCE OF FUNDS (see instructions)

  WC

  CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) or 2(e)

  ☐

  CITIZENSHIP OR PLACE OF ORGANIZATION

  Delaware

NUMBER OF

SHARES

 BENEFICIALLY 

OWNED BY

EACH

REPORTING

PERSON

WITH

  SOLE VOTING POWER

  0

  SHARED VOTING POWER

  2,549,307 (1)

  SOLE DISPOSITIVE POWER

  0

  SHARED DISPOSITIVE POWER

  2,549,307 (1)

  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

  2,549,307 (1)

  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (see instructions)

  ☐

  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

  9.1% (2)

  TYPE OF REPORTING PERSON (see instructions)

  PN

All shares are held of record by PP VII. PMC VII is the general partner of PP VII and may be deemed to have voting, investment and dispositive power with respect to these securities. The Managing Members are the managing members of PMC VII. Ms. Schulman, a member of the Issuers board of directors, holds an interest in PMC VII. Each of the Managing Members and Ms. Schulman may be deemed to share voting, investment and dispositive power with respect to these securities.

Based on 28,066,795 shares of the Issuers Common Stock outstanding as of November 3, 2021, as reported on the Issuers Form 10-Q.

CUSIP No. 78472W104

   NAMES OF REPORTING PERSONS

  Polaris Entrepreneurs Fund VII, L.P.

  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions)

  (a)  ☐        (b)  ☒

  SEC USE ONLY

  SOURCE OF FUNDS (see instructions)

  WC

  CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) or 2(e)

  ☐

  CITIZENSHIP OR PLACE OF ORGANIZATION

  Delaware

NUMBER OF

SHARES

 BENEFICIALLY 

OWNED BY

EACH

REPORTING

PERSON

WITH

  SOLE VOTING POWER

  0

  SHARED VOTING POWER

  178,341 (1)

  SOLE DISPOSITIVE POWER

  0

  SHARED DISPOSITIVE POWER

  178,341 (1)

  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

  178,341 (1)

  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (see instructions)

  ☐

  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

  0.6% (2)

  TYPE OF REPORTING PERSON (see instructions)

  PN

All shares are held of record by PPE VII. PMC VII is the general partner of PPE VII and may be deemed to have voting, investment and dispositive power with respect to these securities. The Managing Members are the managing members of PMC VII. Ms. Schulman, a member of the Issuers board of directors, holds an interest in PMC VII. Each of the Managing Members and Ms. Schulman may be deemed to share voting, investment and dispositive power with respect to these securities.

Based on 28,066,795 shares of the Issuers Common Stock outstanding as of November 3, 2021, as reported on the Issuers Form 10-Q.

CUSIP No. 78472W104

   NAMES OF REPORTING PERSONS

  Amy Schulman

  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions)

  (a)  ☐        (b)  ☒

  SEC USE ONLY

  SOURCE OF FUNDS (see instructions)

  AF

  CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) or 2(e)

  ☐

  CITIZENSHIP OR PLACE OF ORGANIZATION

  United States of America

NUMBER OF

SHARES

 BENEFICIALLY 

OWNED BY

EACH

REPORTING

PERSON

WITH

  SOLE VOTING POWER

  499,266 (1)(2)

  SHARED VOTING POWER

  2,727,648 (3)

  SOLE DISPOSITIVE POWER

  499,266 (1)(2)

  SHARED DISPOSITIVE POWER

  2,727,648 (3)

  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

  3,226,914 (1)(2)(3)

  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (see instructions)

  ☐

  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

  11.4% (4)

  TYPE OF REPORTING PERSON (see instructions)

  IN

Consists of (i) 22,204 shares of the Issuers Common Stock held directly of record by Ms. Schulman and (ii) 201,201 shares of the Issuers Common Stock subject to stock options granted to Ms. Schulman in her capacity as a director of the Issuer that are exercisable as of the date of filing of this Statement (as defined in Item 1 below) or within 60 days thereafter.

275,861 of these shares are held of record by LSPIF (as defined in Item 2(a) below). LSPIF GP (as defined in Item 2(a) below) is the general partner of LSPIF. Ms. Schulman is the sole managing member of LSPIF GP. Each of LSPIF GP and Ms. Schulman may be deemed to have investment, voting and dispositive power over these shares.

Consists of (i) 2,549,307 shares held of record by PP VII and (ii) 178,341 shares held of record by PPE VII. PMC VII is the general partner of each of PP VII and PPE VII and may be deemed to have voting, investment and dispositive power with respect to these securities. The Managing Members are the managing members of PMC VII. Ms. Schulman, a member of the Issuers board of directors, holds an interest in PMC VII and may each be deemed to share voting, investment and dispositive power with respect to these securities.

Based on 28,267,996 shares of the Issuers Common Stock outstanding, which consists of (i) 28,066,795 shares of the Issuers Common Stock outstanding as of November 3, 2021, as reported on the Issuers Form 10-Q and (ii) 201,201 shares of the Issuers Common Stock subject to stock options granted to Amy Schulman in her capacity as a director of the Issuer that are exercisable as of the date of filing of this Statement or within 60 days thereafter.

/s/ Lauren Crockett