Defence group Cobham on Monday said its £2.57bn offer for UK-based rival Ultra Electronics had been agreed.
Cobham is offering £35 a share and “legally binding and enforceable commitments” to the UK government on national security matters.
Dorset-based Cobham, known for its pioneering air-to-air refuelling technology, was bought last year by US private equity firm Advent International. Its American ownership has raised national security concerns in Britain.
Both Cobham and Ultra companies have respective technologies used in the US F-35 and Eurofighter Typhoon jets.