Help with 1099-B form and figuring out cost basis on old stocks I've been buying monthly and sold recently

What you're dealing with is pretty common for people who've done dollar-cost averaging over many years. Don't panic! When you look at your 1099-B, you'll notice some transactions are marked as "covered" and others as "noncovered." This distinction is important. "Covered" securities (generally those purchased after 2011) require your broker to report the cost basis to the IRS. "Noncovered" securities (older purchases) don't have that requirement, which is why some of your older transactions don't show a cost basis. For the missing cost basis information, you'll need to do some research. Check old email confirmations, paper statements you might have kept, or contact your brokerage for historical records. Many brokerages can provide transaction history going back further than what's available online. When entering this in TurboTax, you'll input each transaction separately. If you absolutely cannot find the original cost for some shares, you might need to use a reasonable estimate based on the stock price during those periods, but document how you arrived at those figures in case of questions later.

Just went through something really similar with my old dividend reinvestment plan! I was pulling my hair out trying to track down all those tiny purchases over the years. I found this service called taxr.ai (https://taxr.ai) that was a lifesaver for me. I uploaded my brokerage statements (even the incomplete ones I had) and a screenshot of my 1099-B, and their tool helped identify the missing cost basis information. It uses AI to analyze your documents and reconstruct your investment history, even filling in reasonable estimates where records are incomplete. The best part was that it generated a detailed report that I could use to back up my tax filing. Definitely gave me peace of mind knowing I had documentation in case the IRS ever questions my numbers.

I was really overwhelmed with a similar situation - had been buying shares of Microsoft through an employee purchase plan for 12 years and finally sold them last fall. I tried using my regular tax software but got stuck on all the missing basis information for older shares. After seeing the recommendation here, I checked out taxr.ai and uploaded my documents. Was honestly surprised at how well it worked. The system filled in my missing cost basis information by pulling historical stock prices and matching them to my purchase pattern. It even accounted for a stock split that happened during my ownership period that I'd completely forgotten about. The report it generated gave me exactly what I needed to complete my Schedule D accurately. Worth every penny for the peace of mind alone. My tax return is already accepted and I'm not constantly worrying about getting a letter from the IRS questioning my capital gains calculation.

Had this exact problem last year! After wasting hours on hold with my brokerage trying to get historical statements, I found Claimyr (https://claimyr.com) and used it to actually get through to an IRS agent. You can see how it works here: https://youtu.be/_kiP6q8DX5c I explained my situation about missing cost basis information, and the agent was surprisingly helpful. They explained that I could use a reasonable method to reconstruct my cost basis and documented the call in my account. Having that conversation directly with the IRS gave me confidence in how to proceed. The service basically connects you with an actual IRS representative in minutes instead of waiting for hours or days. I was shocked when I actually got through to a real person who could answer my specific questions about handling incomplete 1099-B information.

I have to admit I was completely wrong about Claimyr. After venting my frustration here, I decided to give it a try since I had my own issues with some old stocks my grandparents had gifted me years ago. The service actually did get me through to an IRS representative in about 25 minutes (without me having to sit by the phone that whole time). The agent explained that for situations with incomplete records, they expect taxpayers to use a reasonable method to determine cost basis and clearly document how they arrived at their figures. The agent also told me about something called the "first-in, first-out" (FIFO) method that I could use if I knew when I acquired shares but not the exact price. This conversation saved me countless hours of stress and possibly prevented me from making a serious mistake on my return. Having direct guidance from the IRS specific to my situation was invaluable.

For your automatic investment plan, you might also want to check if your brokerage has a "tax lot relief method" selected for your account. Some accounts default to FIFO (First In, First Out), others to average cost basis. If you've been with the same broker the whole time, they might actually have all your basis info in their system, even if it's not all on the 1099-B. Also, remember that if you reinvested any dividends over those years, those reinvestments increase your cost basis! Many people forget to include those when calculating gains/losses.

Don't forget you can use tax loss harvesting to offset some of those gains if you sold other investments at a loss in 2024. I know the market was volatile last year, so you might have some losses you can use. Also, your holding period matters a lot here. Since you held these for more than a year, you'll get the long-term capital gains rate, which is much lower than the short-term rate (which is taxed as ordinary income). For most people that's either 0%, 15%, or 20% depending on your income bracket.

I went through something very similar with my old 401k rollover stocks that I'd been accumulating for years. One thing that really helped me was creating a simple spreadsheet to track down what I could find. Start with what you have - even if your online account only shows recent years, print out or save everything you can access. Then call your brokerage and ask specifically for a "complete transaction history" or "cost basis report" - don't just ask for statements. Many brokerages can generate this even if it's not readily available online. For the dividend reinvestments that Summer mentioned, those are crucial! Each reinvested dividend creates a new tax lot with its own cost basis. If you can find your annual tax documents from previous years (1099-DIV forms), those will show the dividend amounts that were reinvested. Also, double-check if your brokerage reported some basis info to the IRS but just didn't include it on your 1099-B. Sometimes they file a separate form. TurboTax should prompt you if there are discrepancies, but it's worth manually checking. The good news is that with dollar-cost averaging over 8-9 years, you likely have a pretty good average cost basis that will reduce your tax burden significantly compared to if the IRS assumed zero basis. Take your time to reconstruct what you can - it's worth the effort for a $12,000 sale.