>Say the tax brackets are rewritten for 2025, starting “January 1”
U.S. income taxes are calculated on an annual basis, not hourly, so that is not an issue. (Wages are taxed according to when they are paid, which is a specific point in time, not according to when they were earned). A better example is trying to figure which calendar (tax) year an item of income or deduction belongs to. On tax professional forums, there are occasional discussions about what happens if I make a business payment online just before New Year's Day begins, but the recipient doesn't "constructively receive" it until after (or similar scenarios involving time zone differences). Do I get a deduction for the old year, but they have income in the new year? (The best answer, of course, is to not wait until a few hours before a deadline to conduct business transactions of this type, but not every type of business has that choice available).
U.S. income taxes are calculated on an annual basis, not hourly, so that is not an issue. (Wages are taxed according to when they are paid, which is a specific point in time, not according to when they were earned). A better example is trying to figure which calendar (tax) year an item of income or deduction belongs to. On tax professional forums, there are occasional discussions about what happens if I make a business payment online just before New Year's Day begins, but the recipient doesn't "constructively receive" it until after (or similar scenarios involving time zone differences). Do I get a deduction for the old year, but they have income in the new year? (The best answer, of course, is to not wait until a few hours before a deadline to conduct business transactions of this type, but not every type of business has that choice available).