Defence firm BAE Systems has concluded its £2.2bn ($4.5bn) takeover of US military manufacturer Armor Holdings.
BAE builds the British Army's Challenger tanks
The deal, which will hugely expand BAE's US business, was announced in May but was subject to regulatory approval, which has now been completed.
BAE faces a probe by US authorities into whether its business dealings comply with anti-corruption laws.
Its role in a huge 1980s arms deal with Saudi Arabia has come under scrutiny, but the firm has denied any wrongdoing.
Analysts have warned that the US Department of Justice probe could potentially hurt BAE's business in the country.
The Armor deal, which could ultimately increase BAE's sales by $3bn (£1.6bn), was approved by the US government last month.
"The acquisition is a significant step in the implementation of BAE's strategy to develop as the premier global defence and aerospace company," it said in a statement.