ETERGINO THOMAS J (Chief Financial Officer) exercised options at 1STDIBS.COM, INC.

Option exercise — a mechanical event triggered by vesting or expiry. Not a discretionary conviction trade.

M · 4 exercises

ETERGINO THOMAS J

Filed: 3/11/2026ACC: 0001336088-26-000002

InsiderETERGINO THOMAS JCIK 1336088

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Issuer1STDIBS.COM, INC.CIK 1600641

Officer· Chief Financial Officer

Since Mar 2022

-19.11K

Net shares

Net seller

$104.9K

Total sold

Open market trades

0B · 0S

Total transactions

53.01K acquired · 72.13K disposed

Non-Derivative Transactions5

Common Stock

Direct

M · Option Exercise

+14.10K

Price / share

—

Trade value

—

% of position

5.3%

3/9/2026

266.88K→280.99K

Common Stock

Direct

M · Option Exercise

+16.56K

Price / share

—

Trade value

—

% of position

5.9%

3/9/2026

280.99K→297.55K

Common Stock

Direct

M · Option Exercise

+11.18K

Price / share

—

Trade value

—

% of position

3.8%

3/9/2026

297.55K→308.73K

Common Stock

Direct

M · Option Exercise

+11.17K

Price / share

—

Trade value

—

% of position

3.6%

3/9/2026

308.73K→319.90K

Common Stock

Direct

F · Tax Withholding

−19.11K

Price / share

$5.49

Trade value

$104.93K

% of position

6.0%

3/9/2026

319.90K→300.79K

Total

Net shares

+33.90K

Net value

-$104.93K

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Common Stock Direct	3/9/2026	M · Option Exercise	+14.10K	—	—	5.3%	266.88K	280.99K
Common Stock Direct	3/9/2026	M · Option Exercise	+16.56K	—	—	5.9%	280.99K	297.55K
Common Stock Direct	3/9/2026	M · Option Exercise	+11.18K	—	—	3.8%	297.55K	308.73K
Common Stock Direct	3/9/2026	M · Option Exercise	+11.17K	—	—	3.6%	308.73K	319.90K
Common Stock Direct	3/9/2026	F · Tax Withholding	−19.11K	$5.49	$104.93K	6.0%	319.90K	300.79K
Total			+33.90K		-$104.93K

Derivative Transactions4

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

14.10K shares

−14.10K

Strike price

Held after

0.00

Exercisable

—

3/9/2026

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

16.56K shares

−16.56K

Strike price

Held after

16.56K

Exercisable

—

3/9/2026

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

11.18K shares

−11.18K

Strike price

Held after

89.40K

Exercisable

—

3/9/2026

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

11.17K shares

−11.17K

Strike price

Held after

134.06K

Exercisable

—

3/9/2026

Security	Converts To	Date	Type	Shares	Exercisable	Held After
Restricted Stock Units Direct	Common Stock14.10K shares	3/9/2026	M · Option Exercise	−14.10K	—	0.00
Restricted Stock Units Direct	Common Stock16.56K shares	3/9/2026	M · Option Exercise	−16.56K	—	16.56K
Restricted Stock Units Direct	Common Stock11.18K shares	3/9/2026	M · Option Exercise	−11.18K	—	89.40K
Restricted Stock Units Direct	Common Stock11.17K shares	3/9/2026	M · Option Exercise	−11.17K	—	134.06K