Quick question - I heard somewhere that forming an S-Corp instead of an LLC can save on taxes? I'm currently a single-member LLC but wondering if I should change how my business is taxed.

Great question about LLC deductions! As others have mentioned, the key is that expenses must be "ordinary and necessary" for your business. I'd also add that you need to be careful about the business vs. personal use distinction - it's not just about percentages, but about maintaining proper records. One thing I haven't seen mentioned yet is the importance of keeping your LLC properly maintained from a legal standpoint. If you're mixing personal and business expenses without clear documentation, or not maintaining proper corporate formalities, you risk "piercing the corporate veil" which could eliminate your LLC's liability protection entirely. For official guidance, definitely start with IRS Publication 535 as Romeo mentioned, but also check out Publication 334 (Tax Guide for Small Business) which has specific sections on LLCs. The IRS website also has a business expenses section that's pretty comprehensive. My advice: when in doubt, err on the side of caution. The penalties for claiming improper deductions can be severe, and the stress of an audit isn't worth trying to push borderline expenses through.

Grace, I completely understand your frustration and panic - that $31,750 penalty would have me losing sleep too! The good news is that you have multiple strong factors working in your favor for a successful first-time abatement request. Based on all the success stories shared here, I'd recommend a two-pronged approach: 1) Use one of the AI-powered services like taxr.ai that several people mentioned to help draft a comprehensive abatement letter with proper legal language and IRS precedent citations, and 2) Use a callback service like Claimyr to actually speak with an IRS agent in the Employee Plans department who can flag your account and provide specific guidance. Your situation checks all the boxes for first-time abatement: clean compliance history, immediate filing once you discovered the requirement, and genuine lack of awareness (not willful non-compliance). The fact that you filed in December 2022 right after learning about it actually strengthens your case - it shows good faith effort rather than waiting until you got caught. Don't let this consume your mental health. From everything I'm reading here, the IRS appears to be quite reasonable with these Solo 401k penalty abatements when you approach it properly. You've got a strong case and plenty of good strategies from this community to work with!

Grace, I'm so sorry you're dealing with this massive penalty - I can only imagine how stressful this must be for you! Reading through all these responses gives me hope that you have a really strong case for first-time abatement. What strikes me most about your situation is that you proactively filed the 5500-EZ in December 2022 as soon as you discovered the requirement. That's exactly the kind of good faith compliance behavior the IRS looks for when considering penalty relief. You didn't ignore it, you didn't wait until you got caught - you took immediate action to correct an honest oversight. Based on everyone's experiences shared here, it seems like the IRS is actually quite reasonable with these Solo 401k penalties when taxpayers have clean compliance histories and approach the situation properly. The combination of a well-crafted abatement letter (maybe using one of those AI services people mentioned) plus a direct conversation with the right IRS department seems to be the winning formula. I know it's easier said than done, but try not to let this consume you with stress. From what I'm reading, you have all the right factors for a successful abatement: clean tax history, immediate corrective action when you learned about the requirement, and genuine lack of prior knowledge about this obscure filing requirement that most tax software doesn't even mention. Please keep us updated on how your case progresses - I'm rooting for you to get this resolved quickly!

For anyone still struggling with this, I wanted to share one more approach that worked for me when I was in a similar bind. If you have access to your bank statements from last year, you can sometimes piece together helpful information for filing Form 4852. Look for direct deposit entries from your employer - these will show your net pay amounts and dates. While this doesn't give you the tax withholding details directly, it can help you verify the accuracy of information you calculate from your final paystub. Also, don't forget to check if you received any year-end bonus payments or expense reimbursements that might have been processed separately from your regular payroll. These could affect your total wages reported on the W-2, and they're easy to miss when you're trying to reconstruct everything from memory and paystubs. If you do end up filing Form 4852, I'd recommend being slightly conservative with your estimates rather than aggressive. It's better to potentially owe a small amount when you eventually get your actual W-2 information than to claim too much in withholdings and face penalties. You can always amend your return later once you have the official documents. The stress of dealing with unresponsive employers during tax season is real, but there really are multiple pathways to get this resolved. Don't panic - you have options!

One additional resource that might help is contacting your state's tax agency. Many state tax departments have procedures for helping residents get W-2 information when employers are unresponsive, and they sometimes have more direct enforcement power over local businesses than federal agencies do. In some states, the tax department can actually compel employers to provide missing W-2s more quickly than going through federal channels. They may also be able to provide you with state wage information that mirrors what's on your federal W-2, which can help you verify your Form 4852 estimates if you end up going that route. I'd also recommend checking if your former employer has any social media presence or online reviews where other former employees might have mentioned similar issues with getting tax documents. Sometimes you can find useful information about alternative contact methods or discover that this is a widespread problem that might get the attention of labor authorities. The key thing is to start pursuing multiple options simultaneously rather than waiting for one approach to fail before trying the next. With tax deadlines approaching, having several backup plans in motion can save you a lot of stress!

Friendly reminder to also check your state tax requirements! Not all states tax capital gains the same way as the federal government. Some states fully tax capital gains as ordinary income, some have their own capital gains rates, and a few don't tax capital gains at all.

Great question about the Washington capital gains tax! You're correct that Washington's new 7% capital gains tax (RCW 82.87) only applies to certain types of capital assets, and personal vehicles are specifically excluded. The tax applies to gains from stocks, bonds, business interests, and similar financial assets, but not to personal property like cars, boats, or household items. So for your car sale situation, you'd only need to worry about federal capital gains tax, not the Washington state tax. This is actually one of the few advantages of Washington not having a general state income tax - most capital gains on personal property aren't subject to additional state taxes here. Just make sure you keep good records showing it was a personal vehicle and not held for business purposes, since that distinction could matter for other tax implications.

Something else to consider - are either you or your ex itemizing deductions? Remember that mortgage interest and property taxes only help if you're itemizing rather than taking the standard deduction. With the standard deduction being $13,850 for single filers in 2025, you'd need your total itemized deductions (including these housing expenses plus charitable contributions, etc.) to exceed that amount for itemizing to make sense. If one of you itemizes and the other takes the standard deduction, it might be more tax-efficient for the itemizing person to claim a larger share of these expenses if that's something you can work out between yourselves.

This is such a helpful thread! I'm dealing with a similar situation where my sister and I co-own a rental property but only her name is on the mortgage. We've been splitting all expenses 50/50 but I was worried I couldn't deduct my portion since the 1098 goes to her. From what everyone's saying here, it sounds like as long as I can document my payments (which I can - we have a separate account just for property expenses that we both contribute to), I should be able to claim my half of the mortgage interest. Has anyone dealt with this specifically for rental property, or is it the same principle as primary residence mortgages? Also really appreciate the tip about keeping a written agreement - definitely going to draft something up with my sister to document our arrangement. Better to be over-prepared than scrambling if questions come up later!