Shares in JLT, which employs more than 4,000 people in the UK, soared by 32 per cent in early trading on Tuesday after the deal was announced.
The bid values JLT at $6.4bn and will see the company’s shareholders receive £19.14 per share, a premium of almost 34 per cent to the closing price on Monday.
Marsh employs more than 65,000 people around the world, with operations in 130 countries.
The company said it expects the deal will help it to reduce expenses by about $250m, partly through job cuts.
Based on preliminary evaluations, Marsh said, it expects potential headcount reduction of between 2 and 5 per cent of the total combined group workforce. JLT employs over 10,000 people, meaning the potential number of jobs lost could be more than 3,500.
Marsh chief executive Dan Glaser said the acquisition “creates a compelling value proposition for our clients, our colleagues and our shareholders”.
“The complementary fit between our companies creates a platform to deliver exceptional service to clients and opportunities for our colleagues,” he said.
“On a personal level, I have come to know, and respect, Dominic Burke and his management team from my time both at MMC and as an underwriter. I am confident that with the addition of the talented colleagues of JLT, Marsh & McLennan will be an even stronger and more dynamic company.”
Mr Burke, JLT’s chief executive, said: “I am enormously proud of what JLT has achieved, founded on our people, our culture and our unwavering commitment to our clients. MMC is, and always has been, one of our most respected competitors and I believe that, combined, we will create a group that will truly stand as a beacon for our industry.”