This excerpt taken from the NDAQ 10-Q filed May 9, 2008.
Non-U.S. Market Services Revenues
Non-U.S. Market Services revenues are also derived from Execution Services and Market Services Subscriptions revenues. The Execution Services revenues, which include trading and clearing revenues from equity and derivative products traded on the Nordic Exchange, are variable, based on service volumes, and recognized as transactions occur. Market Services Subscriptions revenues are based on the number of presentation devices in service and quotes delivered through those devices. Market Services Subscriptions revenues are recognized in the month that information is provided. Since the Nordic Exchange does not have any cost of revenues or revenue sharing agreements, such as liquidity rebates and brokerage, clearance and exchange fees, EITF 99-19 is not applicable.