X0609 4 2026-09-15 0 0001175151 Cytosorbents Corp CTSO 0001639386 Sobel Alan D. false C/O CYTOSORBENTS CORPORATION 305 COLLEGE ROAD EAST PRINCETON NJ 08540 1 0 0 0 0 Common Stock 2026-09-15 4 P 0 1900 6.12 A 9287 D Common Stock 2026-09-15 4 P 0 500 6.05 A 9787 D Common Stock 2026-09-15 4 P 0 100 6.01 A 9887 D These transactions reported on this Form 4 reflect open market purchases made by the Reporting Person. Includes (i) the following restricted stock units ("RSUs") that will be settled into Common Stock upon vesting upon a "Change in Control" of CytoSorbents Corporation (the "Issuer"), as defined in the CytoSorbents Corporation 2014 Long-Term Incentive Plan (the "Plan"): (a) 165 RSUs granted on March 15, 2018, (b) 300 RSUs granted on February 24, 2017, (c) 250 RSUs granted on June 7, 2016, and (d) 2,750 RSUs granted on April 8, 2015 and (ii) 6,422 shares of Common Stock owned directly by the Reporting Person. Reflects the 1-for-20 reverse stock split effected by the Issuer on September 8, 2026. /s/ Peter J. Mariani attorney-in-fact Alan D. Sobel 2026-09-16