Deduction of late PS contribution

[Cynchbeast]

We have a client (calendar year) who has already made 2015 PS contribution and filed their tax return (no extension). We discovered due to a misunderstanding they contributed less than the minimum required. Can they pay the additional now (2016) for 2015 and deduct in 2016, or must this be a non-deductible contribution for 2015?

[Lou S.]

They can do it now and deduct it in 2016, subject to deductible limits in 2016.

I believe in needs to be deposited by 4/15 to count as an annual addition for 2015. I seem to recall something about with in 30 days of the tax return deadline.

[Belgarath]

Agreed - see 1.415©-1(b)(6)(i)(B). Technically that would make it on or before 4/14, as it is 30 days as Lou mentioned.