Royal & Sun Alliance, the insurer, is to take a £443 million hit after offloading its American business to a management vehicle for £158 million, in a move that finally brings to an end its disastrous experience in the US.

Royal & Sun, which shut the loss-making division three years ago and declared it "strategically non core", will cancel its US-listed shares, delist from the New York Stock Exchange and terminate its registration with the regulator, the Securities and Exchange Commission.

Funding for the sale will come from the future performance of the American operations under the management team, whose vehicle is called Arrowpoint Capital. But Royal & Sun, which will need shareholder approval for the transaction, will inject £151 million of capital into the business once the deal completes.

It is hoping to complete the sale by the end of the year.

Andy Haste, the group chief executive of Royal & Sun, said: "Today's announcement is a significant step for the group. The sale of the US operation is the right deal for our shareholders and US policyholders. The transaction will bring certainty and finality and delivers on our objective of a clean exit from the US."

Since shutting the US arm to new business, Royal & Sun has been actively trying to reduce its exposure. In 2005, the division posted heavy losses after being hit with a rash of asbestos-related insurance claims.

At the half-way stage this year, in August, Royal & Sun said it had turned interim losses of £24 million in the US last year into profits of £6 million for the six months to the end of June.

In March, as he admitted that dealing with the US business would "not be a totally smooth ride", Mr Haste said the insurer was actively exploring "opportunities to accelerate coming off risk" there.

Shares in the insurer closed last night at 144.5p, valuing the group at £4.3 billion.

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