LONDON (Bloomberg) — Old Mutual Plc, South Africa's biggest insurer, replaced Jim Sutcliffe as chief executive officer after the company had US losses of $290 million - including $155 million charge against its Bermuda unit - since August.

Old Mutual fell as much as eight percent in London trading after saying it will inject another $250 million into its Bermuda-based operation, which failed to hedge guarantees on investment products. This year's profit will fall as it takes a $155 million charge against losses in Bermuda and $135 million for write-downs on preferred shares held in Fannie Mae and Freddie Mac, the mortgage companies taken over this week by the US.

Julian Roberts succeeds Sutcliffe after Old Mutual added to the £107 million ($189 million) in charges and provisions it announced last month. With the latest injection, Old Mutual has set aside about $500 million against losses at the Bermuda unit. The company is still working to "draw a line under" the problem, and more write-downs are possible, Roberts said.

"The US has caused more pain and heads had to roll," said Youssef Ziai, a London-based analyst at Royal Bank of Scotland Group Plc, who has a "buy" rating on the stock. "The uncertainty lingers on until we get more clarity in the credit markets and the company puts a figure on these types of losses."

Old Mutual dropped as much as 8.1 pence and was down 3.5 percent at 97.4 pence as of 10.10 a.m. The stock has fallen 42 percent this year, valuing the company at £5.1 billion and making it the second-worst performer in the nine-member FTSE All-Share Life Insurance Index, down 21 percent.

The US losses will reduce the company's 2008 earnings by 2.9 pence a share, Old Mutual said. Life-insurance sales at the American unit will fall as much as 20 percent this year because of the losses, Old Mutual forecast in August.

Old Mutual, which has operations in the US, UK and South Africa, has too many units that are not adequately controlled, Ziai has said.

"The issue we are looking at is to get to the bottom of the exposures we have got," Roberts, 51, told reporters yesterday. "It's work in progress to understand what these exposures are."

Roberts, who has been CEO of the company's Skandia unit since February 2006, was previously finance director of Old Mutual.

Sutcliffe, 52, said in August the company's annuities business in Bermuda guaranteed investors' return and only partially hedged the risks against market declines. He called the unit a "major disappointment", stopped selling the guaranteed annuities, ousted a US manager and started a review of the business.