(Reuters) -Shares in UK's Direct Line Insurance soared over 36% in early trade on Thursday after it rejected a 3.28 billion pound ($4.16 billion) takeover offer from bigger rival Aviva, saying it "substantially undervalued" the company.

Goldman Sachs Group Inc. has switched sides to advise Aviva Plc on its £3.3 billion ($4.2 billion) takeover bid for Direct Line Insurance Group Plc, only eight months after helping the target successfully defend against another suitor.

Shares in Direct Line jumped by more than 40% today on the news it has rejected a £3.25bn ($4.12bn) potential takeover bid from Aviva. As at 14:00 London time, Aviva’s share price had fallen by nearly 3%.

Direct Line’s shares surged as investor’s hoped the rejection might pave the way for a second takeover bid from the U.K.’s largest insurance company

Direct Line Insurance Group Plc shares surged as much as 39% after the insurer rejected a £3.3 billion ($4.2 billion) takeover bid from Aviva Plc, the second suitor it’s rebuffed this year.