Archipelago Holdings, the electronic trading network now owned by the New York Stock Exchange, tried to buy the Philadelphia Stock Exchange for $50m (€39.8m) in late 2004, about the same time it was engaged in merger talks with the NYSE, according to just-unsealed court documents.

One case filed in the Delaware's chancery court said: "Commencing in late 2004, management of the PHLX entered into discussion with Archipelago Holdings. These discussions resulted in an offer to acquire all of the stock of the PHLX for $50m in Archipelago stock and/or partial cash."