(Reuters) -Home Depot said on Monday unit SRS Distribution has agreed to acquire specialty building products distributor GMS for about $4.3 billion, stepping up its efforts to capture more demand from professional contractors. The deal also comes amid threats of a hostile takeover for GMS from billionaire Brad Jacobs-led rival QXO.

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.