One of the biggest mortgage lenders in the U.S. said it would pay $1.75 billion to buy a well-known real-estate brokerage. The deal, once it goes through, could have major consequences for millions of home buyers.

Rocket Companies agreed to acquire Seattle-based Redfin in a $1.75 billion deal that will bring together the nation's largest mortgage

Dan Gilbert's Rocket Companies plans to buy the online real estate brokerage firm Redfin, a $1.75 billion deal that would expand Rocket's presence in all things residential real estate. The all-stock deal was announced Monday morning and, pending approval by Redfin shareholders, is expected to close in the second or third quarter.

Rocket Cos. said Monday it would pay $1.8 billion in stock for the online real-estate agency Redfin Corp. in an effort to make it easier for customers to buy property using their mobile devices.

Rocket Companies’ planned $1.75 billion acquisition of Seattle-based brokerage Redfin sparked questions about a potential competitive threat to fellow Seattle real estate company Zillow Group, another key player in the digital real estate arena.

Rocket Cos. is pushing deeper into the property market with a deal to buy Redfin Corp. that values the real estate listing site at $1.75 billion.

Rocket Companies announced a $1.75 billion deal to acquire Redfin. The mortgage titan hopes to leverage Redfin to take market share.

Redfin CEO Glenn Kelman on the benefits of joining Rocket: "Homes.com is running a Super Bowl ad, and Redfin might not be able to afford that. At least not on our own, but Rocket ran a Super Bowl ad."