Global insurance broker Willis Group has reported a 52% fall in net profit for 2011, fuelling market speculation that its legendary CEO Joe Plumeri will retire next year when he turns 70.

Willis shares lost 10.7% of its value on the New York Stock Exchange after it revealed a fall in yearly income to $US218 million ($202.71 million) from $US455 million ($423.1 million) in 2010.

The fourth-quarter net income also fell savagely to $US39 million ($37.19 million) from $US98 million ($91.12 million) last year.

The decline in profits was driven by a sharp rise in the cost of salaries and severance packages and poor performance in the weak economies of the UK, Ireland and the US.

While annual revenues rose 3.63% to $US3.45 billion ($3.2 billion), expenses grew faster, increasing 10.97% to $US2.86 billion ($2.65 billion).

“We’re obviously not satisfied with results that show low organic growth and declining adjusted operating margins, especially given the peerless record we’ve established in prior years for such measures,” Mr Plumeri said.

The former Citigroup banker has headed Willis since 2000 and floated the London-based global broker on the New York Stock Exchange in 2001.