Web sites that process individual tax returns must follow domain name rules.

      The U.S. Internal Revenue Service has begun enforcing new domain name rules for online tax return services.

      The rules apply to online providers of individual income tax returns that own or operate a Web site through which taxpayer information is collected, transmitted, processed or stored:

-Domain name must be registered with a domain name registrar in the United States
-Registrar must be accredited by ICANN
-Domain name must be locked
-Whois record can’t be private

      The rules went into affect January 1, 2010, but there was a one year grace period for enforcement.

Source from Domain Name Wire