Nasdaq launched a surprise £2.4 billion ($4.1 billion) bid for the London Stock Exchange on Friday. Clara Furse, CEO, responded sharply by stating that the offer was “unexpected and unwelcome”.

A statement from the LSE Board said the proposal — which represents an 8 percent premium to the current market price — “substantially undervalues the company”.

The LSE reiterated that it was still on track to return £510m ($883m) to shareholders, a promise it made after fighting off the Macquarie Bank bid.

“The board has rejected this unsolicited approach and intends to continue with its proposed 200p-per-share ($3.50) capital return.”

Nasdaq returned fire after the rejection by saying it had made an “attractive offer” with “unique benefits” unmatched by other would-be buyers.

“Nasdaq and LSE are both pre-eminent equity markets in their respective countries,” the New York-based technology exchange said in a statement.

“Nasdaq believes that bringing together the two organizations would present listed companies, traders and investors with an equity marketplace, based on dynamic industry leadership to serve their needs, unmatched by any other marketplace in the world.”

Shares in the LSE closed up 1.9 percent at 880p ($15.2) on Friday before the announcement was made, while Nasdaq shares jumped more than 10% to close at $43.56.

Analysts pointed out that a merger of the two companies could generate massive costs savings as it would eventually lead to a single trading platform.

It’s believed that the US bid would not face the same hurdles as Euronext and Deutsche Borse. The British Treasury is known to favour Nasdaq as a partner for the LSE as it would give Britain a strong foothold in the booming American technology market.