ROSENBLATT DAVID S (Chief Executive Officer) sold 3.6% of their position (73.21K shares) of 1STDIBS.COM, INC. on the open market

Open‑market sale worth $436.3K — a minor trim. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 1 sale

ROSENBLATT DAVID S

Filed: 12/10/2025ACC: 0001237860-25-000009

InsiderROSENBLATT DAVID SCIK 1237860

→

Issuer1STDIBS.COM, INC.CIK 1600641

DirectorOfficer· Chief Executive Officer

Since Jun 2021

-73.21K

Net shares

Net seller

$436.3K

Total sold

Open market trades

0B · 1S

Total transactions

132.50K acquired · 205.71K disposed

Non-Derivative Transactions4

Common Stock

Direct

M · Option Exercise

+37.50K

Price / share

—

Trade value

—

% of position

2.0%

12/8/2025

1.92M→1.95M

Common Stock

Direct

M · Option Exercise

+47.50K

Price / share

—

Trade value

—

% of position

2.4%

12/8/2025

1.95M→2M

Common Stock

Direct

M · Option Exercise

+47.50K

Price / share

—

Trade value

—

% of position

2.4%

12/8/2025

2M→2.05M

Common Stock

Direct

S · Sale

−73.21K

Price / share

$5.96

Trade value

$436.31K

% of position

3.6%

12/8/2025

2.05M→1.98M

Total

Net shares

+59.29K

Net value

-$436.31K

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Common Stock Direct	12/8/2025	M · Option Exercise	+37.50K	—	—	2.0%	1.92M	1.95M
Common Stock Direct	12/8/2025	M · Option Exercise	+47.50K	—	—	2.4%	1.95M	2M
Common Stock Direct	12/8/2025	M · Option Exercise	+47.50K	—	—	2.4%	2M	2.05M
Common Stock Direct	12/8/2025	S · Sale	−73.21K	$5.96	$436.31K	3.6%	2.05M	1.98M
Total			+59.29K		-$436.31K

Derivative Transactions3

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

37.50K shares

−37.50K

Strike price

Held after

187.50K

Exercisable

—

12/8/2025

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

47.50K shares

−47.50K

Strike price

Held after

427.50K

Exercisable

—

12/8/2025

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Common Stock

47.50K shares

−47.50K

Strike price

Held after

617.50K

Exercisable

—

12/8/2025

Security	Converts To	Date	Type	Shares	Exercisable	Held After
Restricted Stock Units Direct	Common Stock37.50K shares	12/8/2025	M · Option Exercise	−37.50K	—	187.50K
Restricted Stock Units Direct	Common Stock47.50K shares	12/8/2025	M · Option Exercise	−47.50K	—	427.50K
Restricted Stock Units Direct	Common Stock47.50K shares	12/8/2025	M · Option Exercise	−47.50K	—	617.50K

Non-Derivative Holdings (Post-Transaction)2

Common Stock

Indirect

Shares owned22.50K

Common Stock

Indirect

Shares owned665.30K

Total

687.80K indirect687.80K

Security Title	Shares Owned	Ownership Type
Common Stock	22.50K	Indirect
Common Stock	665.30K	Indirect
Total	687.80K	687.80K indirect

Derivative Holdings (Post-Transaction)0

No derivative holdings reported