Long story short, a self employed person missed the 10/15/18 deadline for their 2017 SEP contribution (lots of reasons, but I don’t think any exemption / relief applies (in the Hurricane Harvey disaster area, spouse was in hospital leading up to the deadline, etc). It wasn’t caught until now 2019. So even putting the funds in now wouldn’t general a tax year 2018 form 5498. They did put the deduction on their return however, just didn’t fund it.

I’m assuming an amended 2017 return should be done to take the deduction back out, however a little research brings another question.

from my research, the only language I am finding is this:

“Self-employed persons are not allowed to deduct overdue SEP plan contributions on that year’s return. If you did not request an extension and missed to deposit funds to employee SEP IRAs by the due date of filing your tax return, those overdue contributions may be deducted when filing the following year’s return.”

The phrase “those overdue contributions may be deducted when filing the following year’s return”. Does that mean that he could take the deduction on his 2018 tax return based on his 2017 earnings (IE the same amount he originally claimed), AND ALSO properly take a SEP deduction for 2018 based on his 2018 self employment earnings? or is his deduction in 2018 limited to being based on his 2018 earnings