Aon and Willis Towers Watson have stressed that having a “one firm” mindset will be key as top appointments are confirmed for the combined company after a $US30 billion ($39 billion) merger is completed.

The companies have released regional and other management appointments that draw on personnel from both firms after last year confirming Aon’s Greg Case as CEO, Aon’s Christa Davies as CFO and Willis Towers Watson CEO John Haley as Executive Chairman,

“As we learned more about each other’s organisations, it became clear that a fundamental driver of our success will be leaders who fully embrace a one firm mindset,” Mr Haley said.

“The willingness to put the needs of clients and the entire organisation ahead of their part of the business and any individual priorities will be the key to unlocking the full potential of the planned combination for the benefit of all our stakeholders."

The firms say Eric Andersen will be President, North America will be led by Alexis Faber, Asia-Pacific by Anne Corona, the UK by Julie Page and Europe, the Middle East and Africa by Eduardo Davila. For Latin America, the company named Luis Maurette as CEO and Alejandro Galizia as President.

In the Commercial Risk segment, Lambros Lambrou was named CEO and Adam Garrard President and CEO, Global Broking.

A number of other executive appointments in reinsurance and other areas have also been named.

Aon has confirmed the European Commission has initiated a Phase II review of the merger, which will create the world’s largest broker, but the deal remains on track for completion in the first half of this year.

The company is yet to make any announcements on key appointments for Australia and New Zealand.