GMS Investor Presentation Deck

Track Record of Successful Platform Expansion Completed 90+ acquisitions and greenfields since May 2014. All U.S. yard locations are fully integrated into the GMS platform Since August 2014, GMS has acquired 45 companies representing a total of ~126 distribution locations Since August 2014, GMS has opened an additional -49 organic greenfield locations, complementing acquisition strategy Since acquiring AMES Taping Tools in December 2021, GMS has opened 14 new AMES store locations GMS GYPSUM MANAGEMENT & SUPPLY, INC. Date May-23 Apr-23 Apr-23 Mar-23 Jan-23 Nov-22 Acquisition/Greenfield LUMBER & BUILDING SUPPLIES BLAIR BUILDING MATERIALS INC. M E INC., J Ottawa New York City South Richmond Select Recent GMS Expansion Locations ■ 1 Location - Victoria, m BC ■ 1 Location - Toronto, ON area ■ 4 Locations - Chicago, Atlanta, Charlotte Ottawa, ON Brooklyn, NY ▪ Chester, VA m M m Strategic Rationale H Margin-accretive Complementary Products acquisition in desirable Vancouver Island market Margin-accretive Complementary Products acquisition adding new product lines in the Greater Toronto area ▪ New location for D.L. Building Materials expansion in Ottawa Strategic Chicago area acquisition to increase market serviceability and gain access to key vendor relationships Inaugural location focused on Ceilings products in the New York City market Expands market service coverage in the Richmond, VA market for Commonwealth Building Materials As of June 2023 10

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