contribution deadline extended to July 15 for PLLC

I'm pretty sure of the answer, but my client has already filed the 2019 tax return and wants to know if he can make the contribution by July 15th.

I believe he's out of luck since the return has already been filed.

You are wrong.

See Q&A 20 here:  https://www.irs.gov/newsroom/filing-and-payment-deadlines-questions-and-answers

What was the due date before the recent IRS extension?

If it was April 15, then it has been extended to July 15. If the PLLC is taxed as a sole proprietorship then this is probably the case.

If it was anything other than April 15, it is unchanged. If the PLLC is taxed as an S corp or as a partnership then its return and contribution were probably due as of March 15, unless an extension was filed timely.

20 hours ago, thepensionmaven said:

I'm pretty sure of the answer, but my client has already filed the 2019 tax return and wants to know if he can make the contribution by July 15th.

I believe he's out of luck since the return has already been filed.

Assuming the return was due 4/15 (Sole Prop or C Corp) and not 3/15 (Partnership or S Corp), then his due date is 7/15 and he has until that time to make the contribution. There has always been some controversy regarding if you can get an extension (which would be until 10/15) if you actually file the return prior to the first regular due date, but many people take the position that you can.  I prefer to tell clients who want to file by the first regular due date to go on extension and file the return the day after the regular due date; that guarantees that your extended contribution date is valid.