This excerpt taken from the NDAQ 8-K filed Dec 11, 2006.
Information Reporting and Backup Withholding
In general, backup withholding will apply to dividends on our common stock paid to a non-U.S. holder, unless the holder has provided the required certification that it is a non-U.S. holder and the payor does not have actual knowledge (or reason to know) that the holder is a U.S. person. Generally, information will be reported to the Internal Revenue Service regarding the amount of dividends paid, the name and address of the recipient, and the amount, if any, of tax withheld. These information reporting requirements apply even if no tax was required to be withheld. A similar report is sent to the recipient of the dividend.
In general, backup withholding and information reporting will apply to the payment of proceeds from the disposition of our common stock by a non-U.S. holder through a U.S. office of a broker or through the non-U.S. office of a broker that is a U.S. person or has certain enumerated connections with the United States, unless the holder has provided the required certification that it is a non-U.S. holder and the payor does not have actual knowledge (or reason to know) that the holder is a U.S. person.
Backup withholding is not an additional tax. Any amounts that are withheld under the backup withholding rules from a payment to a non-U.S. holder will be refunded or credited against the holders U.S. federal income tax liability, if any, provided that certain required information is furnished to the Internal Revenue Service.
Non-U.S. holders should consult their tax advisors regarding the application of the information reporting and backup withholding rules to them.