As New York Mercantile Exchange shareholders consider selling a stake in the exchange to private equity group General Atlantic, they would be well-advised to look across lower Manhattan at the New York Stock Exchange for clues about what lay ahead.

Nymex shareholders are not happy about the board's decision last week to recommend that 10 per cent of the privately owned exchange be sold to General Atlantic for $135m, and rival bidders are asking for explanations. Investors are also talking among themselves about ways to oust the incumbent 25-member board, and replace it with a smaller one.