Q: As an F-1 visa holder elected as a resident alien, should I provide W-9 or W-8 for U.S.-based fellowship compensation?

A: As an F-1 visa holder who has elected to be treated as a resident alien for tax purposes by filing jointly with your U.S. citizen spouse, your tax filing requirements have changed. The IRS indicates that "a dual status J-1 alien married on the last day of the taxable year to a U.S. citizen or to a resident alien may elect with his or her spouse to file a joint Form 1040 return as if the J-1 visa holder was a U.S. resident alien for the entire tax year." While this specifically mentions J-1 visas, the same principle applies to F-1 visa holders who make this election.

For your fellowship compensation, you should provide Form W-9 to the payer. The IRS guidance states that when individuals "become a U.S. resident for federal tax purposes" and want to claim tax benefits, they "must give the withholding agent a Form W-9, Request for Taxpayer Identification Number." This contradicts the W-9 instructions you mentioned, but the specific guidance for individuals who have made the election to be treated as a resident alien takes precedence over the general instructions.

Remember that your election to be treated as a resident alien changes your tax status comprehensively. When you file jointly with your U.S. citizen spouse, making an "election under IRC § 6013(g), Election to Treat Nonresident Alien Individual as Resident of the United States," you "must file as a U.S. resident in subsequent years" until this election is terminated. This means all your U.S. income, including fellowships, should be handled according to resident alien rules.