By Adriano Marchese

The U.K.'s Competition and Market Authority said Tuesday that it believes that the acquisition by Stryker Corp. of Wright Medical Group NV is or may result in substantial lessening of competition in the country.

The regulator said that it is considering whether to accept an undertaking in lieu of a reference--which would mean that the parties have until July 7 to offer a pledge or promise that might be accepted by the CMA.

Last November, Dutch medical-devices maker Wright Medical agreed to be acquired by Stryker for about $4 billion--or $30.75 a share--in cash.

Write to Adriano Marchese at adriano.marchese@wsj.com