Form 4 Filing for David S. Rosenblatt

This filing details transactions by David S. Rosenblatt, Chief Executive Officer of 1stdibs.com, Inc., on September 8, 2026. Rosenblatt acquired a total of 174,167 shares of Common Stock through the settlement of Restricted Stock Units (RSUs). Specifically, 37,500 RSUs vested and were settled, resulting in the acquisition of 37,500 shares. Similarly, 47,500 RSUs, another 47,500 RSUs, and 41,667 RSUs vested and were settled, each resulting in the acquisition of the same number of shares. These RSUs were granted on various dates between March 2023 and March 2026, with vesting occurring in quarterly installments. Additionally, Rosenblatt disposed of 96,229 shares of Common Stock at a price of $4.73 per share. This disposal was to cover tax withholding obligations related to the vesting of RSUs. The filing also notes indirect holdings of Common Stock through two family trusts: the 2024 Laura Thalheimer Rosenblatt Family Trust holding 22,500 shares and the 2012 David Rosenblatt Family Trust holding 712,802 shares.