Home Depot's push into the pro market began in earnest last year, when the company dropped $18.5 billion to buy SRS Distribution.

Home Depot bought SRS Distribution — the subsidiary that’s acquiring GMS — last year for $18.25 billion, in the largest acquisition in its history. Texas-based SRS sells supplies to professionals in the landscaping, roofing and pool businesses and it has bought up many other smaller suppliers as it’s grown.

Home Depot has entered an agreement to buy GMS INC for about $4.3 billion, a leading specialty building products distributor on Monday.