Did you do all this yourself or hire someone? I'm in a similar situation but wondering if tax software can handle unfiled business returns from previous years or if I need a professional.

I started with tax software but quickly realized I was in over my head with the business portion, especially for multiple unfiled years. I ended up hiring a CPA who specializes in small businesses and self-employment taxes, and it was 100% worth the cost. The CPA found numerous deductions I would have missed, like partial deductions for my car when used for business purposes and some home expenses beyond just the home office. They also helped me structure my payment plan with the IRS when I couldn't pay the full amount right away. If your situation involves any complexity at all with business income, I'd recommend a professional. The peace of mind alone was worth it, and the money they saved me in deductions more than covered their fee.

How long did it take before the IRS took action? Were there warning notices first or did they just start garnishing out of nowhere?

I double-checked both my E*TRADE account and the transaction confirmations - there was definitely no "sell to cover" for taxes. The statements explicitly show 0% withholding on these vestings. All shares came through intact with no sales. I think I'm going to follow the advice about contacting our stock admin team specifically rather than regular HR. It sounds like there's something wrong with how my international transfer was set up in their system.

That's definitely a problem then. One other thing to check - some companies use a different payroll system for equity compensation than they do for regular salary. So while your ADP might show nothing, there could be withholding happening in a different system. This happened to me when I transferred from our Tokyo office. My regular pay was in ADP but equity was handled through a specialized system that didn't show up in my regular payroll login. Check with your stock admin team if they use a separate system for equity compensation reporting.

The general rule is that RSUs are taxed based on where you are when they vest, not where you were when they were granted. So if you're a US resident/taxpayer when they vest, the entire value at vesting is taxable in the US regardless of where you earned them. There can be exceptions based on tax treaties between countries and the specific structure of your equity plan, but in most cases, if you're physically in the US when RSUs vest, they're fully taxable in the US. You might want to check if there's a US-Canada tax treaty provision that applies to your specific situation.

1 What exactly should I be keeping? Just the W-2C and copies of the amended return? Or should I also be keeping some kind of documentation about when I received it from my employer?

5 You should definitely keep the original W-2C (both your copy and all copies they sent you), your original tax return for that year, and copies of your completed amended return with all attachments. I'd also recommend keeping any emails or documentation showing when you received the W-2C from your employer, especially since it came so late. I'd also suggest writing a brief explanation letter to attach to your amended return explaining the delayed W-2C situation. This helps the IRS processor understand why you're amending a return from two years ago. In my case, including this letter helped when I had to follow up later.

22 I work in payroll, and you're partly right. There's been a big push for compliance audits after all the remote work and state tax complications from the pandemic. Many companies are still catching up and finding issues from 2-3 years ago. Plus the IRS has been sending more notices about mismatches between what employers reported and what employees filed.

How do you determine if something is a PFIC? I own shares in a few foreign companies through my brokerage account and have no idea if they qualify.

A corporation is generally considered a PFIC if either 75% or more of its gross income is passive income (like dividends, interest, royalties) OR at least 50% of its assets produce passive income or are held to produce passive income. For publicly traded companies, you can sometimes find this information in their annual reports or investor information. For privately held companies, you might need to request this information directly from the company. Some brokerages also provide PFIC statements for foreign stocks they know qualify. If you can't get the information to make this determination, the IRS may assume it's a PFIC and the burden falls on you to prove otherwise. That's why international tax situations can get complicated quickly.

Good point about tax treaties. I've found that using the IRS's Tax Treaty Table on their website helps figure out if there's a treaty and what the withholding rates should be. Different countries have different rates for various types of income.

Does ProSeries have an option for non-accountants? I thought it was only available to professional preparers with credentials.

You're right, I should have mentioned that limitation. ProSeries is only available to professional tax preparers with PTINs (Preparer Tax Identification Numbers). If you're doing this yourself without professional credentials, you wouldn't be able to purchase it directly. Your options would be either going with consumer software like TurboTax Business (though it gets expensive with multiple entities), using a specialized platform like the taxr.ai that others mentioned, or hiring a professional who uses ProSeries/Drake/similar professional software.

This is super important advice. I'd add that you should also check if the software can handle special allocations if your operating agreement has provisions for that. We have carried interest provisions for the manager in our LLC and TaxAct couldn't handle it properly.