Foreign persons with a U.S. trade or business, including but not limited to:

  • U.S. trade or business;
  • Partnerships and trusts;
  • Banking;
  • Management of real property;
  • Determining effectively connected income;
  • Effect of tax treaty provisions;
  • Permanent establishment; and
  • Branch profits tax.

Foreign persons with nonbusiness U.S. source income, including but not limited to:

  • General withholding rules, subject to treaties;
  • Fixed or determinable annual or periodic (FDAP) income;
  • Treaty shopping, and defenses to treaty shopping;
  • Responsibilities of withholding agents; and
  • Foreign investment in U.S. real property (FIRPTA).