The AW139 was developed in collaboration between Agusta and Bell as AB139 and later continued by Agusta alone. After the merger of Agusta (IT) and Westland (UK) into AgustaWestland, today Leonardo Helicopters, it is called AW139. Today, the AW139 is the market leader among medium helicopters and more than 900 units have been produced in Italy, the US and Russia.