X0609 4 2026-08-31 0 0001442236 Quest Resource Holding Corp QRHC 0001448795 FRIEDBERG DANIEL M. false C/O QUEST RESOURCE HOLDING CORPORATION 433 E. LAS COLINAS BOULEVARD, SUITE 675 IRVING TX 75039 1 0 1 0 0001773816 Hampstead Park Capital Management, LLC false 6 LIGHTHOUSE LANE OLD GREENWICH CT 06870 0 0 1 0 0001773840 Hampstead Park Environmental Services Investment Fund LLC false 6 LIGHTHOUSE LANE OLD GREENWICH CT 06870 0 0 1 0 0 Common Stock 2026-08-31 4 A 0 19942 1.40 A 165597 D Common Stock 97068 D Common Stock 2842353 I By: Hampstead Park Environmental Services Investment Fund LLC These reported securities represent restricted stock units ("RSUs") granted on August 31, 2026 under the Issuer's 2024 Incentive Compensation Plan. Each RSU represents a contingent right to receive one share of common stock upon vesting. The RSUs are scheduled to vest on March 1, 2027. Includes (a) 87,745 RSUs that are scheduled to fully vest on March 1, 2027, (b) 28,767 RSUs that are scheduled to fully vest on August 13, 2027 and (c) 49,085 shares of common stock beneficially owned by Mr. Friedberg. The reported securities include (a) 18,153 deferred stock units ("DSUs") granted under the Issuer's 2012 Incentive Compensation Plan and (b) 78,915 DSUs granted under the Issuer's 2024 Incentive Compensation Plan. The shares of common stock underlying such DSUs shall be issued upon Mr. Friedberg's separation from service with the Issuer. This Form 4 is filed jointly by Hampstead Park Environmental Services Investment Fund LLC ("Hampstead Park Environmental"), Daniel Friedberg and Hampstead Park Capital Management, LLC ("Hampstead Park Capital"). Hampstead Park Capital is the sole member of Hampstead Park Environmental, and Mr. Friedberg is the Chief Executive Officer of Hampstead Park Capital; each may therefore be deemed to control Hampstead Park Environmental. In addition, Mr. Friedberg is a Director of the Issuer. /s/ Daniel Friedberg 2026-09-02 Hampstead Park Capital Management, LLC; By: /s/ Daniel Friedberg, Chief Executive Officer 2026-09-02 Hampstead Park Environmental Services Investment Fund LLC; By: Hampstead Park Capital Management, LLC; By: /s/ Daniel Friedberg, Chief Executive Officer 2026-09-02