David Pauling - 01 Mar 2026 Form 4 Insider Report for SUTRO BIOPHARMA, INC. (STRO)

Role
Chief Admin. Ofcr. & GC
Signature
/s/ David Pauling
Issuer symbol
STRO
Transactions as of
01 Mar 2026
Net transactions value
-$31,212
Form type
4
Filing time
03 Mar 2026, 18:59:49 UTC
Previous filing
29 Dec 2025
Next filing
06 Mar 2026
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Pauling David Chief Admin. Ofcr. & GC C/O SUTRO BIOPHARMA, INC., 111 OYSTER POINT BLVD., SOUTH SAN FRANCISCO /s/ David Pauling 03 Mar 2026 0002063633

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction STRO Common Stock Options Exercise $0 +500 +7% $0.000000 7,673 01 Mar 2026 Direct
transaction STRO Common Stock Options Exercise $0 +842 +11% $0.000000 8,515 01 Mar 2026 Direct
transaction STRO Common Stock Tax liability $11,279 -551 -6.5% $20.47 7,964 01 Mar 2026 Direct F1
transaction STRO Common Stock Options Exercise $0 +2,356 +30% $0.000000 10,320 02 Mar 2026 Direct
transaction STRO Common Stock Tax liability $19,934 -970 -9.4% $20.55 9,350 02 Mar 2026 Direct F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction STRO Restricted Stock Units (RSUs) Options Exercise $0 -500 -50% $0.000000 500 01 Mar 2026 Common Stock 500 Direct F2, F3
transaction STRO Restricted Stock Units (RSUs) Options Exercise $0 -842 -33% $0.000000 1,686 01 Mar 2026 Common Stock 842 Direct F2, F4
transaction STRO Restricted Stock Units (RSUs) Options Exercise $0 -2,356 -25% $0.000000 7,069 02 Mar 2026 Common Stock 2,356 Direct F2, F5
transaction STRO Restricted Stock Units (RSUs) Award $0 +4,200 $0.000000 4,200 02 Mar 2026 Common Stock 4,200 Direct F2, F6
transaction STRO Stock Option (right to buy) Award $0 +33,600 $0.000000 33,600 02 Mar 2026 Common Stock 33,600 $20.55 Direct F7
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of RSUs; does not represent a sale by the reporting person.
F2 Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.
F3 The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2024, subject to continued service through each vesting date.
F4 The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2025, subject to continued service through each vesting date.
F5 The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 2, 2026, subject to continued service through each vesting date.
F6 The RSUs shall vest as to 1/4 of the total award annually, with the first tranche vesting on March 1, 2027, subject to continued service through each vesting date.
F7 1/48 of the total option award shall vest monthly, subject to the reporting person's continued service to the Issuer on each vesting date, with the first tranche vesting on April 1, 2026.

Remarks:

Effective as of 12:01 a.m. Eastern time on December 3, 2025, pursuant to a Certificate of Amendment to the Issuer's Restated Certificate of Incorporation previously approved by the Issuer's stockholders, and filed with the Delaware Secretary of State on December 2, 2025, the Issuer's Common Stock, par value $0.001 per share, underwent a 1-for-10 reverse stock split (the "Reverse Stock Split"). All amounts, including all dollar values, set forth herein have been adjusted to reflect the Reverse Stock Split.