Charles Schwab, the US discount brokerage giant, was on Thursday forced to say that it was not for sale, amid heavy speculation on Wall Street that the company was negotiating a deal.

The statement, unusual in the US where it is uncommon for companies to comment on rumours, followed heavy trading in Schwab options and a surge in its share price, which rose as much as 15 per cent on Thursday before closing up 5 per cent to $12.60. "We have no interest in selling the company," said Charles Schwab, the firm's founder who was reappointed chief executive last year.