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

Mortgage giant Rocket Companies announced Monday it struck a deal to purchase digital real estate brokerage Redfin in an all-stock deal valued at $1.75 billion.

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.

One of the biggest mortgage lenders in the U.S. announced this week that it plans to buy a well-known real-estate brokerage — and the deal, once it goes through, could have major consequences for millions of home buyers.