X0609 4 2026-03-19 0 0001210708 Star Equity Holdings, Inc. STRR 0001779155 Diamond Matthew K false C/O STAR EQUITY HOLDINGS, INC. 53 FOREST AVENUE, SUITE 101 OLD GREENWICH CT 06870 0 1 0 0 Chief Accounting Officer 0 Common Stock 2026-03-19 4 A 0 3993 0 A 21489 D Common Stock 2026-03-19 4 F 0 551 9.92 D 20938 D On January 24, 2025 (the "Grant Date"), the restricted stock units ("RSUs") were granted to the Reporting Person under the Issuer's 2009 Incentive Stock and Awards Plan, as amended and restated (the "2009 Incentive Plan") for which the performance conditions related to vesting were satisfied as of March 19, 2026. The RSUs granted are subject to time-based vesting conditions that vest 33% on the first anniversary of the Grant Date (1,318 RSUs), 33% on the second anniversary of the Grant Date (1,318 RSUs), and 34% on the third anniversary of the Grant Date (1,357 RSUs). This number represents shares of Star Equity Holdings, Inc. Common Stock withheld to satisfy the tax withholding obligation due upon vesting of performance-based restricted stock units. Includes (i) 6,889 RSUs credited to the Reporting Person's account under the Issuer's 2009 Incentive Plan; and (ii) 14,049 shares of common stock. Each RSU is the economic equivalent of one share of Common Stock. RSUs may be settled pursuant to the 2009 Incentive Plan by the issuance of Common Stock, the payment of cash, or a combination of both. /s/ Matthew K. Diamond 2026-03-23