Just be careful with all this. I used the adjusted cost basis last year thinking it was correct, and ended up getting a CP2000 notice from the IRS saying I underreported my capital gains because the basis I used didn't match what my broker reported. Had to file an amended return and pay the difference plus interest. Such a headache!

I've been dealing with ESPP tax issues for years and want to clarify a few things based on my experience. The key is understanding that when you purchase ESPP shares at a discount, that discount is typically treated as compensation income and should appear on your W-2 in the year you bought the shares (not when you sold them). If you can find your W-2 from the year you purchased the ESPP shares, look for the discount amount included in your wages. If it's there, then you should definitely use the adjusted cost basis to avoid being taxed twice on the same money. However, if for some reason the discount wasn't included in your W-2 when you purchased (which can happen with some plan structures), then you'd use the regular cost basis and pay tax on the discount as part of your capital gains. The most important thing is to use Form 8949 with the proper adjustment code when your basis differs from the 1099-B. Don't just enter a different number without explanation - that's what triggers those CP2000 notices people mentioned. I'd also recommend keeping detailed records of your ESPP purchases, including purchase dates, discount amounts, and whether those discounts were included in your W-2 income. This documentation will be invaluable if you ever need to justify your basis calculations to the IRS.

Just wanted to add that if you do end up filing Form 4852 as a substitute for your W-2, make sure to keep detailed records of all your attempts to get the corrected information from your employer. The IRS may ask for documentation showing that you made a good faith effort to obtain the correct W-2. Also, since you moved from Nevada to Arizona mid-December, you'll likely need to file as a part-year resident in Arizona. Arizona has specific rules about when you become a resident for tax purposes, and since your employer was withholding Arizona taxes the whole time, you may actually owe additional state taxes or be entitled to a refund depending on how long you were actually an Arizona resident. I'd recommend checking Arizona's part-year resident requirements on their Department of Revenue website before filing to make sure you're handling the residency piece correctly along with the missing W-2 information.

This is a great discussion with lots of helpful advice! I just wanted to add one more option that might help if you're still stuck waiting for your employer to respond. You can also try contacting the Arizona Department of Revenue directly at (602) 716-6932. Since it sounds like Arizona is the state that withheld your taxes, they might be able to help you identify your employer's state ID number if you provide them with your employer's name and federal EIN (which should be in box b on your W-2). Arizona's tax department is generally pretty responsive, and they deal with this issue frequently. They can sometimes look up the employer in their system and provide you with the missing state ID information over the phone. This could save you from having to wait for a corrected W-2 if your employer continues to drag their feet. Also, since you mentioned using TurboTax, they have a feature where you can enter "Unknown" for the state ID temporarily and then amend your return later once you get the correct information. It's not ideal, but it's an option if you're running up against the deadline and still don't have the corrected form.

Quick tip - if you're filing an amended return, make sure you pay any additional tax owed as soon as possible even if the amended return takes months to process. The IRS charges interest on unpaid taxes from the original due date (usually April 15th), not from when they process your amendment. This caught me off guard when I had to amend last year. I waited until my amendment was processed to pay, and ended up with interest charges I wasn't expecting!

I went through this exact same situation two years ago! Forgot a W-2 from a part-time job that was only about $280. I was terrified about penalties but here's what I learned: The IRS is actually pretty understanding when you voluntarily amend before they catch the mistake. I used TurboTax's amendment feature and it walked me through everything step by step. The hardest part was honestly just printing and mailing the 1040X since you can't e-file amendments. One thing that helped calm my nerves was calling the IRS practitioner priority line (if you have a CPA or enrolled agent help you) or using one of those callback services others mentioned. Getting confirmation that my amendment was received properly gave me so much peace of mind. The whole process took about 4 months to fully resolve, but no penalties since I was proactive about it. Don't let the anxiety eat at you - just get the amendment filed and you'll be fine!

Don't forget about state tax issues! Depending on your state, you might have franchise tax or entity-level taxes that are affected by the change from partnership to single-member LLC. In California for example, the $800 minimum franchise tax applies differently to partnerships vs. disregarded entities. Also, if you have any registered intellectual property like trademarks or patents in the LLC's name, you'll want to document that these remain with the entity through the transition. Some states also require notification to any LLC registered agents when ownership changes by more than a certain percentage.

Michigan has pretty straightforward requirements for LLC ownership changes. You'll need to file an amendment to your Articles of Organization with the state if your operating agreement requires it, but many standard LLCs don't actually require this filing just for membership changes. For taxes, Michigan follows federal treatment pretty closely - your LLC will be disregarded for state tax purposes once you become the sole member, so you'll report business income on your individual Michigan return instead of filing a separate entity return. No special franchise tax issues like California. One thing specific to Michigan - if you have any state tax credits or incentives tied to the LLC (like Renaissance Zone benefits or certain business development programs), make sure those don't get affected by the ownership change. The Michigan Department of Treasury sometimes requires notification for significant ownership changes in entities receiving state benefits. Also document your digital assets and domain ownership clearly in your buyout agreement. Even though they're not "registered IP" yet, having a clear record of what stays with the LLC will save headaches later if you do end up filing for patents or trademarks on your software.

I've been struggling with this exact same issue for over a month now! Reading through all these responses, I think I've been making the classic mistake of overthinking it. I've tried probably 20 different variations of my address format, but I never thought to check what the IRS actually has on file for me in their system. What really resonates with me is the suggestion about using old IRS correspondence as a reference - I definitely have some notices from last year that I can dig up. I've also been trying during my lunch break like a lot of people probably do, so the off-peak hours approach makes total sense. The most frustrating part is that generic "invalid address" error message that tells you absolutely nothing about what's actually wrong. It could be a missing comma, wrong abbreviation, or their servers just having a bad day. I appreciate everyone sharing their specific solutions because the IRS website's help section is basically useless for troubleshooting this stuff. Going to try the all-caps approach combined with the exact format from my last IRS mailing tonight when fewer people are using the system. Fingers crossed! 🤞

I'm dealing with this exact same frustrating issue right now! After reading through everyone's experiences, it's clear the IRS address validation system is just poorly designed. What strikes me most is how many different "solutions" people have found - from all-caps formatting to removing punctuation to trying old IRS correspondence as a reference. I think the key takeaway here is that their system doesn't match addresses the way a normal person would expect. It's not just checking if your address exists, but whether it matches their very specific internal formatting rules that seem to change randomly. I'm going to try the combination approach: find my last IRS notice, copy that address format exactly (including capitalization and spacing), clear my browser cache completely, and attempt access during off-peak hours. If that doesn't work, I'll request the transcript by mail and use that to see exactly how they have my address formatted in their system. Thanks to everyone who shared their specific solutions - it's way more helpful than the generic "contact the IRS" advice you get from their official help pages!