Not sure if anyone mentioned this, but there are some exceptions to the estimated tax penalty! If your total tax minus withholding is less than $1,000, you won't face a penalty. Also, if you had no tax liability last year (a 12-month period), you can avoid penalties regardless of this year's situation. And sometimes the IRS will waive penalties for reasonable cause like natural disasters or other unusual circumstances.

Just wanted to add my experience here! I was in almost the exact same situation last year - both my spouse and I are W2 employees and we underpaid significantly. We ended up making a January 15th estimated payment, but honestly wish we had known about the W-4 strategy earlier. The January payment did help reduce our penalty, but we still owed some because the IRS calculates penalties quarterly. If you still have paychecks coming before year-end, definitely consider increasing your withholding through a new W-4 first - that's the best way to completely avoid penalties since it's treated as paid evenly throughout the year. Also, double-check if you qualify for any of the safe harbors mentioned. We found out we could have paid just 100% of our prior year's tax liability (since our AGI was under $150k) rather than trying to estimate our current year's liability, which made the calculation much simpler.

Has anyone with a similar situation looked into how the QBI phase-out thresholds might affect this decision? As a physician, OP is in a specified service trade or business, so QBI phases out at higher income levels. Wondering if structuring as S-corp vs sole prop affects how those thresholds are calculated.

This is a great discussion! I'm actually a tax professional who works with a lot of physicians in similar situations. A few additional considerations that might help with your decision: 1. **State taxes matter**: If you're in a state with high income taxes, the S-corp structure might provide additional benefits since you'll avoid state income tax on the self-employment tax portion. 2. **Bookkeeping complexity**: S-corps require more formal bookkeeping, payroll processing, and quarterly filings. Make sure to factor in these additional costs when comparing structures. 3. **Timing flexibility**: With a sole prop, you have more flexibility in when you recognize income and expenses. With an S-corp, you're locked into paying yourself that reasonable compensation throughout the year. 4. **Future scalability**: If you plan to expand your moonlighting or add employees, an S-corp structure might be easier to scale. Given your numbers ($200k W-2 + $150k business income), you're likely in the QBI phase-out range, which actually makes the S-corp structure more attractive since you'll get less QBI benefit anyway. The self-employment tax savings of roughly $11,475 on $75k of distributions would probably outweigh the reduced QBI deduction. Have you considered whether your employer has any restrictions on outside business activities that might affect your choice of structure?

Don't forget there's a social security and Medicare impact too, not just income tax! Since med premiums should have been pre-tax, employees also overpaid on FICA taxes. Your company likely also overpaid the employer portion of these taxes. You should file a Form 941-X for each affected quarter to get your employer portion refunded, and the W-2c process will help employees get their overpaid portion back. Some payroll systems can help you calculate exactly how much was overpaid by each party.

This is a really tough situation, but you're handling it responsibly by trying to make it right for your employees. I went through something similar when our previous payroll company miscoded our dependent care FSA contributions. One thing I'd add to the great advice already shared - consider sending a clear, simple letter to all affected employees along with their W-2c forms explaining exactly what happened, what it means for them, and what their options are. We found that many employees were initially confused or even worried when they received corrected tax documents, thinking they had done something wrong. In our letter, we included a simple table showing "If your original refund was X and your corrected refund would be Y, your additional refund would be Z." This helped employees quickly see if filing an amendment would be worthwhile for their situation. We also set up a dedicated email address and phone line for questions about the correction, which really helped reduce confusion and showed employees we were taking ownership of the mistake. The transparency went a long way toward maintaining trust with our staff. Given your industry and the timing, you might also want to consider offering to reimburse filing fees for amendments over a certain threshold (like $200 in additional refund) to make the decision easier for employees who would benefit most from filing.

Random but important question - are both your names on the deed AND the mortgage? Because if only one of you is legally obligated on the mortgage, only that person can claim the interest regardless of who makes payments!

I had a very similar situation with my husband before we were married! We also used a private family loan and were splitting payments. Here's what I learned after consulting with a tax professional: The key issue is that the IRS requires you to have both legal obligation AND actual payment to claim the deduction. If both your names are on the mortgage documents, you each have legal obligation, but you can only deduct what you personally paid. The "retroactive payment shuffling" idea your father-in-law's accountant suggested could be problematic. The IRS looks at the substance of transactions, not just paperwork after the fact. If you're audited, they'll want to see bank records showing who actually made payments when. However, you still have some legitimate options for this tax year: 1) If you haven't made all 2024 payments yet, change who makes the remaining payments to optimize your situation, 2) Make additional principal payments before year-end from your account to shift the balance, or 3) Consider if filing separately vs. jointly (once married) would be better overall. For next year, definitely restructure your payment arrangement from the start. Have the higher earner make all mortgage payments while the other covers utilities, groceries, etc. This gives you maximum flexibility for tax planning. Don't risk audit issues by trying to recharacterize payments that already happened - focus on legitimate strategies moving forward!

Does anyone know if employee discounts count as taxable income? I work retail and get 40% off merchandise. My manager said it's completely tax-free but that sounds too good to be true lol.

Great question about employee discounts! Your manager is mostly right, but there are some nuances. Employee discounts on merchandise are generally tax-free as long as the discount doesn't exceed your employer's gross profit percentage. So if your company has a 50% markup on products, a 40% employee discount would be completely tax-free. However, if the discount exceeds the gross profit margin, the excess becomes taxable income. For services (rather than merchandise), employee discounts are tax-free up to 20% off the regular customer price. Since you're getting 40% off and it sounds like your employer considers it non-taxable, they've likely determined that their markup is high enough to cover your discount. Retail often has substantial markups, so a 40% employee discount staying within tax-free limits is definitely plausible!