ETERGINO THOMAS J (Chief Financial Officer) sold 9.2% of their position (27.07K shares) of 1STDIBS.COM, INC. on the open market

Open‑market sale worth $161.3K — a moderate reduction. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 1 sale

ETERGINO THOMAS J

Filed: 12/10/2025ACC: 0001336088-25-000004

InsiderETERGINO THOMAS JCIK 1336088

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Issuer1STDIBS.COM, INC.CIK 1600641

Officer· Chief Financial Officer

Since Mar 2022

-27.07K

Net shares

Net seller

$161.3K

Total sold

Open market trades

0B · 1S

Total transactions

53.01K acquired · 80.08K disposed

Non-Derivative Transactions5

Common Stock

Direct

M · Option Exercise

+16.56K

Price / share

—

Trade value

—

% of position

6.9%

12/8/2025

240.94K→257.50K

Common Stock

Direct

M · Option Exercise

+14.10K

Price / share

—

Trade value

—

% of position

5.5%

12/8/2025

257.50K→271.60K

Common Stock

Direct

M · Option Exercise

+11.18K

Price / share

—

Trade value

—

% of position

4.1%

12/8/2025

271.60K→282.78K

Common Stock

Direct

M · Option Exercise

+11.17K

Price / share

—

Trade value

—

% of position

4.0%

12/8/2025

282.78K→293.95K

Common Stock

Direct

S · Sale

−27.07K

Price / share

$5.96

Trade value

$161.31K

% of position

9.2%

12/8/2025

293.95K→266.88K

Total

Net shares

+25.95K

Net value

-$161.31K

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Common Stock Direct	12/8/2025	M · Option Exercise	+16.56K	—	—	6.9%	240.94K	257.50K
Common Stock Direct	12/8/2025	M · Option Exercise	+14.10K	—	—	5.5%	257.50K	271.60K
Common Stock Direct	12/8/2025	M · Option Exercise	+11.18K	—	—	4.1%	271.60K	282.78K
Common Stock Direct	12/8/2025	M · Option Exercise	+11.17K	—	—	4.0%	282.78K	293.95K
Common Stock Direct	12/8/2025	S · Sale	−27.07K	$5.96	$161.31K	9.2%	293.95K	266.88K
Total			+25.95K		-$161.31K

Derivative Transactions4

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

16.56K shares

−16.56K

Strike price

Held after

33.13K

Exercisable

—

12/8/2025

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

14.10K shares

−14.10K

Strike price

Held after

14.10K

Exercisable

—

12/8/2025

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

11.18K shares

−11.18K

Strike price

Held after

100.58K

Exercisable

—

12/8/2025

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

11.17K shares

−11.17K

Strike price

Held after

145.24K

Exercisable

—

12/8/2025

Security	Converts To	Date	Type	Shares	Exercisable	Held After
Restricted Stock Units Direct	Common Stock16.56K shares	12/8/2025	M · Option Exercise	−16.56K	—	33.13K
Restricted Stock Units Direct	Common Stock14.10K shares	12/8/2025	M · Option Exercise	−14.10K	—	14.10K
Restricted Stock Units Direct	Common Stock11.18K shares	12/8/2025	M · Option Exercise	−11.18K	—	100.58K
Restricted Stock Units Direct	Common Stock11.17K shares	12/8/2025	M · Option Exercise	−11.17K	—	145.24K