Shares in Aviva, the UK's biggest insurer, jumped last Friday after reports that it could be the target of a takeover by a foreign buyer, The Guardian reported.
Its shares rose as much as 10% at one point on 6 October before closing 5% higher at 407.9p, valuing the company at £11.2bn and catapulting it to the top of the FTSE 100 index.
Other UK insurance stocks, including Legal & General, Prudential and Phoenix, also rose.
The markets blog Betaville and the Times newspaper reported that Aviva had attracted takeover interest from several international rivals.
It has previously been linked with Germany's biggest insurer, Allianz, while Canada's Intact Financial Corporation and the Danish insurer Tryg are reportedly considering their options, along with a US insurer, with a £6-a-share proposal mooted, according to the Times.
A City source told the Guardian there had been some discussions with discussions with suitors.
There was no statement from Aviva or any of the other companies.
