How would I know if the basis wasn't reported? Is there something specific to look for on the form? Because I think this might be exactly my issue.

Look at your 1099-B form from your brokerage - there should be a column that indicates whether the cost basis was reported to the IRS. Sometimes there's a checkbox, other times it might say "Covered" versus "Noncovered" transactions, or it might explicitly state "Cost basis not reported to IRS" for certain transactions. Noncovered securities (typically those acquired before certain dates or transferred from other brokerages) don't have their cost basis automatically reported to the IRS, so the IRS only sees the sale proceeds. In those cases, they might assume your entire proceeds are gains unless you properly report the cost basis on Form 8949.

Will the IRS just cancel the debt if I can show the broker's forms match what I reported? Or will I need to prove something more?

This is exactly right. Business losses from scams are still deductible as business expenses if they occurred in the normal course of business. It's only personal theft losses that got eliminated (except for federally declared disasters). OP, was this investment somehow connected to any business activities or was it purely personal? That makes a huge difference in deductibility.

You can also try contacting CFPB (Consumer Financial Protection Bureau) if a bank or financial institution was involved in any way with the transactions. They sometimes can put pressure on financial institutions that may have facilitated the scam.

Thanks for the suggestion! I did file a report with IC3 already but haven't heard anything back yet. It's been about 3 months since I filed the report. I'll check out the CFPB option too. My bank wasn't much help since I authorized the transfers myself (stupid, I know), but maybe CFPB could still do something.

Just checked my pay stub and it does say "Single" for filing status, but there's nothing about multiple jobs. I do max out my 401k ($22,500/year) and have an HSA that I put about $3,000 into annually. Could those really affect my withholding that much? I thought those were smart financial moves.

Those are absolutely smart financial moves! The issue isn't that you're doing anything wrong - it's that the withholding system doesn't always account for them perfectly. When you contribute to 401k and HSA, your taxable income for each paycheck is lower, so the system withholds less tax. However, those contributions don't reduce your tax brackets - they just reduce your total taxable income. If you're near a bracket threshold, this can create a withholding gap. This explains the difference between you and your coworkers too. If they're not maxing retirement accounts, their withholding calculation is more straightforward. Your situation is actually financially better (huge retirement savings), but it requires manual adjustment to your withholding to avoid the surprise tax bill.

The IRS calculator isn't technically broken, but it's not great for complex situations. It works best for people with one job, standard income, and no special circumstances. The moment you add variables like education expenses, multiple income sources, or significant pre-tax deductions, it falls apart. I found the calculator on smartasset.com to be much more accurate for estimating actual withholding needs. It lets you input more details about your specific situation.

Thanks, I'll check out that other calculator. I was starting to think I was going crazy because I followed the IRS calculator recommendations exactly and still ended up owing over $2k. Good to know it's not just me!

Is that seriously true that both spouses have to choose the same deduction method?? I had no idea! We were planning to have my husband itemize since he has tons of deductible expenses while I'd take the standard deduction. Will this really not work?

Yes, it's absolutely true and it's one of the biggest "gotchas" with married filing separately. If one spouse itemizes, the other MUST also itemize - even if they have very few deductions. This often means the second spouse ends up with a very small itemized deduction amount that would have been much better served by taking the standard deduction. This requirement often wipes out much of the potential benefit of filing separately, which is why it's so important to run the numbers both ways. The tax code deliberately makes MFS less advantageous in most situations to encourage joint filing.

I've had similar experiences with TurboTax too. These programs often show "refund estimates" before they've calculated everything. Sometimes they don't include state taxes or certain penalties until the very end of the process.

Is that still true? I thought they changed that rule recently?

The PATH Act requirements are still in effect for the 2025 filing season. There have been no changes to this law. If you claim EITC or ACTC, the earliest you would see your refund is around February 15th, regardless of when you file. The IRS uses this time to verify income reported on W-2s and 1099s against the credits claimed to prevent fraudulent refunds. While there are occasionally discussions about modifying these rules, no actual changes have been implemented yet.

That timing makes sense - returns filed closer to the deadline take longer because the IRS gets swamped. I always aim for early February once I have all my documents. Just make sure you have EVERYTHING before filing!