Typically the deadline to make a deductible employer discretionary contribution is the due date, plus extensions, of the employer's tax return. If the employer is a nonprofit that does not file a tax return, and has no corresponding deduction, what is the deadline?

Why do you not regard Form 990 as being a tax return ?

Because no tax is paid. Also the tax return connenction relates to deductibility of the contribution. If you have no taxable income, there is no deduction, so the deadline could be different.

Do you consider the 5500 a tax return?

Kimberly, I would suggest that the "outside maximum date" would be the close of the following plan year. I know that this does not address the potential of the "due date + 30" for IRC 415, but....

Perhaps you should take a very conservative approach of the funding deadline that would have applied if subject to that timing. Is that legit? No, but...

I have also asked this question in the past. Never got a good answer. Sorry that mine is also of little, or no value.

As alluded to by Below Ground, if Section 415 is at all critical to a tax-exempt, then Treas. Reg. Section 415(c)-1(b)(6)(i)(B) requires that, for purposes of annual addition limitations for the plan of a tax exempt entity, "contributions must be made to the plan no later than the 15th day of the tenth calendar month following the end of the calendar year or fiscal year . . . with or within which the particular limitation year ends" (which is the same rule as for a taxable entity: "30 days after the end of the period described in section 404(a)(6) applicable to the taxable year with or within which the particular limitation year ends"). For many tax exempts, a few of those missed deadlines will produce a violation of IRC Section 415.