(Reuters) -The U.S. government will require Keysight Technologies ( KEYS ) to divest three of Spirent Communications' ( SPNUF ) businesses to resolve antitrust concerns before it buys the British company, a purchase originally valued at $1.5 billion.

In filings on Monday in the Washington, D.C., federal court, the U.S. Department of Justice said the divested assets include Spirent's high-speed ethernet testing, network security testing, and radio frequency channel emulation businesses.

Keysight ( KEYS ) said in March it planned to sell those businesses to Viavi Solutions ( VIAV ), once known as JDS Uniphase, for as much as $425 million in cash.

The Justice Department said Keysight ( KEYS ) and Spirent together account for 85% of the high-speed ethernet testing market, more than 60% of the network security market, and more than 50% of radio frequency channel emulation.

It said a merger without the divestitures might substantially lessen competition and harm customers.

Keysight ( KEYS ) and Spirent did not immediately respond to requests for comment.

Based in Santa Rosa, California, Keysight ( KEYS ) agreed in March 2024 to buy Crawley, U.K.-based Spirent for 1.16 billion British pounds, now about $1.57 billion.

Viavi had agreed earlier that month to buy Spirent, but was outbid by Keysight ( KEYS ).

($1 = 0.74 pounds)