Amid the self-congratulations yesterday as senior executives from the CME Group and Nymex discussed their $9.4bn cash-and-shares takeover deal, there was a strong undercurrent of relief.

Richard Schaeffer, Nymex's chairman, said the CME Group was "the right partner at the right time". A less charitable version might have cast the CME as Nymex's only option not to be left out of the rampant consolidation that has engulfed the exchange world in recent years.