I am a co-trustee on my father's trust along with several other siblings. One of the other co-trustees wants to submit expenses that sibling paid for in a prior year for the trust to reimburse her. I read at the IRS website that expenses paid and incurred in prior years may not be deductible on the trust's tax return. Since I am the one keeping the records, I don't want to do something wrong. Can you please help me with this question?

you are correct; each tax return reports finances for its own year and each of those years needs to be kept separate. Deductions, income or anything else from a previous year cannot be claimed with the current year?s tax information.So, generally speaking, you cannot deduct expenses from a previous year on this year?s tax return. You can only deduct expenses in the year that you paid for them. You can file an amended tax return if you discover a tax deduction you missed in a previous year.