The U.K.'s competition watchdog accepted concessions offered by Welltower offered to get the U.S. real-estate investment trust's acquisition of hundreds of British care homes approved.

The move means Welltower avoids an in-depth investigation into the deal by the Competition and Markets Authority.

Welltower embarked on a $23 billion buying spree in October that included the real-estate portfolio of Barchester Healthcare-operated homes in the U.K. for £5.2 billion ($7.04 billion).

The company also bought care homes from HC-One, Aria Care, Asprey Healthcare and Danforth Care. Under that deal, Care UK and Apex Healthcare Properties--through a partnership with Barchester Healthcare--would have managed day-to-day operations at the care homes.

The watchdog said in May that the transaction could have given Welltower or one of the other managing care-home companies control of a significant proportion of homes across 30 local areas in England and Scotland, potentially raising costs and reducing quality. Welltower then offered to sell a number of properties and move the operations of others to a new provider to ease the regulator's concerns.

"It's crucial that older people and their families choosing care homes get the best care available at a reasonable price," Sorcha O'Carroll, the CMA's senior director of mergers, said in a statement Thursday.

"Having engaged closely with the businesses, we believe Welltower has a solution that could resolve those concerns, allowing us to clear the deal and maintain competition at the same time," she said.