<prompt> Human: A couple of years ago, IRS updated its rules regarding cost basis reporting for brokers. Whereas previously brokers automatically adjusted the purchase price for shares purchased through employee stock purchase plans ESPP for you on your 1099-B, now they cant do so, and this could lead to you erroneously paying more taxes than you owe.What does this mean? Say you bought 1000 worth of company stock through ESPP at a 10 discount so 900 and sold it soon after for 1050. In this particular scenario disqualifying disposition, the initial discount you got 100 will be reported by your employer as ordinary income. Box 1 on your W-2 total wages will likely already include this.The capital gain on this sale is 1050 - 1000 50, but on 1099-B the cost basis for this sale will be 900 rather than 1000, resulting in a reported gain of 150. The 100 discount will therefore get taxed twice, first as ordinary income and again as short term capital gain. Your need to adjust the cost basis for ESPP sales yourself on Schedule D of your 1040 as well as form 8949.I know that Fidelity in particular includes a supplement with your tax forms which details these adjustments, making things easy for you. Im not sure about other brokers. TurboTax guides you through these steps as well.Note that I have described a very particular scenario which might or might not apply to you, and there are many more categories for ESPP taxation that you might fall under. It is best to consult a tax professional with any concerns.  <response>: My employer sends a Form 3922, which you can use in TurboTax to help fill out Form 8949.If you had to calculate it manually with my specific situation disqualifying disposition, with cost basis already reported to IRS - box A checked:I have to use adjustment code B. Manually calculating the adjustment, it was: reported cost basis - total value of stock on purchase date 