The NYSE has a traditional trading floor, but Mr Thain, 48, is seen as an advocate of electronic trading.

NYSE interim chairman and CEO John Reed said Mr Thain was somebody who would "look at the future". Former NYSE chief Dick Grasso quit the post after revelations that he had negotiated a pay and benefits package worth a total of $140m (�80m).

The scale of the pay deal angered investors, who said it cast doubt over standards of governance at the exchange.

Mr Thain will take over his new post on 15 January.

Moves criticised

The announcement came a day after the Securities and Exchange Commission approved the NYSE's proposal to overhaul its governing structure.

Under the reforms, drawn up by John Reed, the exchange would be run by a board of directors with between six and 12 independent members, and a separate 20-member board of executives.

The exchange's activities would also be overseen by a "chief regulatory officer" who would report to a committee of directors.

But the shake-up has already been criticised as inadequate by major investors and US legislators, who argue that it does not do enough to curb the influence of the NYSE's member firms over how the exchange is run.

Under Mr Reed's proposals, NYSE members would retain the power to elect some of its directors.