In one e-mail exchange, a Goldman banker invites colleagues to join in a betting pool on how much Archipelago's stock would jump the day the deal got announced.

FORBES: Careful What You E-Mail!

The Tote will also keep its seven-year monopoly on pool betting (where stakes are pooled and the winners take the lot, minus taxes and an administration charge, as opposed to fixed-odds betting where the bookmaker bears the risk).

ECONOMIST: The Tote: Odd odds | The

Another competition concern is that the Tote's pool-betting monopoly will remain.

ECONOMIST: The Tote