Rocket Cos.’ $9.4 billion planned acquisition of loan servicer Mr. Cooper Group would put one in six U.S. mortgages under Rocket’s purview, according to the companies. That would create a mortgage behemoth.

Rocket, the online mortgage provider, is acquiring Mr. Cooper Group in a deal valued at $9.4 billion creating a combined company that will service a book of $2.1 trillion of loans and nearly 10 million clients.

Less than one month after announcing a plan to acquire digital real estate brokerage firm Redfin for $1.75 billion, the Detroit-based mortgage giant (NYSE: RKT) said it plans to acquire Mr. Cooper Group Inc. (NASDAQ: COOP) in an all-stock deal valued at $9.4 billion.