Has anyone here dealt with this situation where one of the partners is an S-Corp specifically? I'm concerned about the timing since S-Corps have different filing deadlines than partnerships.

One thing I'd add that hasn't been fully addressed - make sure you understand the potential for imputed underpayment assessments under BBA rules. Even though partnerships are pass-through entities, the IRS can assess and collect penalties at the partnership level for certain adjustments. When you file the 1065-X as your AAR, the IRS will review it and may propose an imputed underpayment based on the highest individual tax rate plus Net Investment Income Tax. The partnership can then make a "push out" election to have the adjustment flow through to the partners instead of being assessed at the partnership level. Given that you're dealing with an S-Corp partner, this could be particularly relevant since the ultimate shareholders might be in lower tax brackets than what the IRS would use for the imputed underpayment calculation. You'll want to consider whether to make the push-out election when filing the AAR or wait to see if the IRS proposes an assessment. Also, since you mentioned both partners agree on the correction, document that agreement well. It'll be helpful if the IRS has any questions about the adjustment during their review process.

A quick tip nobody mentioned: If you're filing a super late return like this, send it via certified mail with return receipt requested. This gives you proof of when you submitted it in case the IRS ever questions the filing date. Has saved my butt more than once.

Don't panic! You're actually in a pretty good position since you mentioned you think you were owed a refund for 2021. As others have said, there are no penalties for filing late when you're getting money back from the IRS. One thing I'd add is to double-check that you haven't already filed electronically through a service you might have forgotten about. You can create an account on the IRS website and view your tax transcripts to see what they have on file for 2021. This will show you if anything was already submitted and what your actual refund amount would be. Also, since you have all your documents ready to go, consider using tax software that supports prior year returns rather than trying to fill out the forms by hand. It'll catch calculation errors and make sure you don't miss any deductions. Just remember - you'll need to print and mail it since e-filing isn't available for 2021 returns anymore. The April 18, 2025 deadline is coming up fast, so definitely prioritize getting this done soon if you want to claim that refund!

Has anyone used QuickBooks Time or similar apps for tracking material participation? My accountant suggested it but it seems like overkill for just partnership documentation.

For what it's worth, I've been through a similar situation with health issues affecting my participation hours. One thing that helped me was realizing that time spent on administrative tasks like reviewing financials, insurance matters, vendor negotiations, and even business-related phone calls all count toward material participation - not just the obvious "management" activities. Since you mentioned health issues, don't forget that time spent dealing with business insurance, worker's comp issues, or even reviewing partnership agreements during your recovery could count. I kept a simple daily log in my phone's notes app during my recovery period, just jotting down "reviewed bank statements - 30 min" or "client follow-up call - 15 min" throughout the day. Also, consider the "facts and circumstances" test if you don't hit the hour thresholds. Given that you're a 50% owner actively involved in operations (even if reduced due to health), you might still qualify as materially participating. Documentation becomes even more crucial for this test though.

One thing nobody mentioned is that you might qualify for dual-status filing for 2023. Since you changed from F1-OPT to H1B mid-year, you could potentially file as a nonresident for part of the year and a resident for part of the year. Dual-status filing is complicated though. You basically file 1040-NR for the nonresident portion and attach a 1040 as a statement for the resident portion. Worth asking your CPA about this option too.

Based on your timeline, you definitely should have filed 1040-NR instead of 1040. Here's why: As an F1 student who arrived in September 2021, you're considered an "exempt individual" for your first 5 calendar years (2021-2025). This means: - Your F1 days (Sep 2021 - Dec 2022): Don't count - Your F1-OPT days (Jan 2023 - Sep 2023): Don't count - Your H1B days (Oct 2023 - Dec 2023): Only about 92 days count With only ~92 countable days in 2023, you clearly don't meet the 183-day threshold for the Substantial Presence test. You should file Form 1040-X to amend your return to 1040-NR. This is especially important since you mentioned potential USCIS applications - having incorrect tax filings can definitely complicate future immigration processes. I'd recommend getting this corrected ASAP and keeping documentation of the amendment for your records. Your accountant may not have been familiar with the F1 exempt individual rules, which is unfortunately common. Consider finding a CPA who specializes in nonresident tax issues for future filings.

Has anyone considered the liability issues here? If your parents get in an accident while driving your rental car, who's liable? Your LLC might provide some protection, but with only one asset (the car itself), that protection is pretty limited. Make sure your rental agreement clearly outlines who's responsible for what. Will your parents need to purchase additional coverage when they rent from you, like customers do at regular rental companies? Or will your commercial policy cover everything?

One thing I don't see mentioned yet is the importance of keeping detailed mileage logs for business use vs personal use of the vehicle. Since you'll be using the same car for both personal driving and your rental business, the IRS will want to see clear documentation of what percentage is used for business purposes. You'll need to track every mile driven for business activities - picking up/dropping off the car to your parents, maintenance trips related to the rental business, any marketing activities, etc. This business use percentage will determine how much of your vehicle expenses you can legitimately deduct. Also, make sure you're charging your parents the actual market rate, not a "family discount." The IRS looks closely at related-party transactions, and if you're charging below market rates, they might question whether this is truly a business or just a way to shift personal expenses to a business entity. Check what Hertz, Enterprise, etc. are charging in your area for similar vehicles and match those rates. Keep receipts for everything - gas, maintenance, car washes, registration fees, etc. Even small expenses add up and can be legitimate business deductions if properly documented.