Tax season for the 2026 tax year runs on a fixed calendar, even though the IRS had not named its opening day as of November 2, 2026. The deadlines for sending forms to investors are set in IRS Publication 1099 (2026), and in 2027 two of them land a day late because of a Sunday and a federal holiday. This checklist covers the forms to expect, when each is due, what to check on it and the mistakes that most often lead to amended returns or IRS letters. The explanations behind each item sit in the guides on the stocks hub.
What are the key dates for the 2027 tax season?
The dates that matter run from the January 15 estimated payment to the October 15 extended deadline, with most forms due in early February.
| Date | What is due |
|---|---|
| Friday, January 15, 2027 | Fourth estimated tax payment for 2026 |
| Monday, February 1, 2027 | Forms 1099-DIV, 1099-INT, 1099-OID and 1099-R, plus the Form 5498 statement of year-end value and any RMD |
| Tuesday, February 16, 2027 | Forms 1099-B and 1099-DA, and consolidated broker statements that include them |
| Monday, March 15, 2027 | Schedule K-1 from calendar-year partnerships that do not extend, and statements for widely held fixed investment trusts |
| Thursday, April 15, 2027 | 2026 returns and payments, extension requests, 2026 IRA and HSA contributions and the first 2027 estimated payment |
| Tuesday, June 1, 2027 | Form 5498 and 5498-SA contribution statements for IRAs and HSAs |
| Friday, October 15, 2027 | Extended 2026 returns |
The payer dates move because a form furnished on the next business day counts as on time: January 31, 2027 is a Sunday, February 15 is Washington's Birthday and May 31 is Memorial Day. That turns the usual January 31 and February 15 deadlines into Monday, February 1, 2027 for Forms 1099-DIV, 1099-INT, 1099-OID and 1099-R, and Tuesday, February 16, 2027 for Forms 1099-B and 1099-DA, including consolidated broker statements. A payer can also get up to 30 more days by filing Form 15397 with the IRS, so a late form is not always a lost one.
Returns for 2026 are due Thursday, April 15, 2027, or Friday, October 15, 2027 with an extension, which moves only the filing date and not the date tax is due. The IRS opened the last filing season on January 26, 2026, after announcing the date on January 8. The IRS has also been phasing out paper refund checks since September 30, 2025, so most filers expecting a refund need to give bank routing and account numbers.
Which tax forms should investors expect for 2026?
A taxable brokerage account usually sends one consolidated statement holding several 1099s, while IRAs, HSAs, banks and partnerships each send their own forms.
| Form | What it reports for 2026 | What to check |
|---|---|---|
| 1099-B | Sales of stocks, funds, bonds and options | Box 1e basis, box 1g wash sales, box 5 noncovered lots |
| 1099-DA | Crypto sales through a custodial broker | Basis appears only for covered coins bought in 2026 |
| 1099-DIV | Dividends and fund distributions | Boxes 1b, 2a, 3 and 7 |
| 1099-INT | Interest from banks, bonds and Treasuries | Box 3 Treasury interest, box 8 tax-exempt interest |
| 1099-OID | Discount accruing on long CDs, zero-coupon bonds and STRIPS | Box 8 discount on Treasury obligations |
| 1099-R | IRA and plan withdrawals, rollovers and conversions | The distribution code in box 7 |
| 5498 | IRA contributions, conversions and the December 31 value | The contribution copy comes after the filing deadline |
| 1099-SA and 5498-SA | HSA withdrawals and contributions | Withdrawals should match medical costs |
| Schedule K-1 | Partnership income, including some commodity funds and master limited partnerships | Often the last document to arrive |
Every one of these also goes to the IRS, which matches the figures against returns. How gains, basis and holding periods work is covered in capital gains tax on stocks; the rest of this checklist sticks to what is new or easy to miss for 2026.
How do you check a Form 1099-B before filing?
Compare three boxes with your own records: box 1e for basis, box 1g for wash sales and box 5, which flags lots whose basis was not reported.
The 2026 Form 1099-B instructions require brokers to report a disallowed wash sale loss in box 1g only when the sale and the repurchase happen in the same account and involve covered securities with the same CUSIP number. A repurchase in an IRA, a spouse's account or at another firm will not appear there, so the adjustment is yours to make on Form 8949 with code W, as the wash sale rule guide shows. Shares bought before the basis rules began, generally 2011 for stocks and 2012 for fund shares, may arrive with box 5 checked and no basis. Entering zero would overstate the gain, so take the cost basis from your own records.
Employee stock needs its own check. For options and other equity awards granted from 2014, the instructions bar brokers from adding the income already taxed as wages to basis, and Publication 525 says the adjustment is the taxpayer's job. The fix is code B on Form 8949.
Worked example: Fixing the basis on employee stock purchase plan shares
Riley bought 100 shares through an employee stock purchase plan at $85, a 15% discount to the $100 market price on the purchase date, and sold them in 2026 for $110 each before meeting the plan's holding period.
- Riley's Form W-2 already includes the discount as wages: 100 × ($100 − $85) = $1,500.
- The 2026 Form 1099-B shows proceeds of $11,000 and basis of $8,500, which suggests a $2,500 gain.
- The correct basis adds the $1,500 of wages: $8,500 + $1,500 = $10,000, so the capital gain is $1,000.
- Reporting the form as printed would tax $1,500 twice. On Form 8949, Riley enters code B and an adjustment of −$1,500 in column (g).
What does Form 1099-DA show for 2026 crypto sales?
It shows cost basis for the first time, but only for covered coins bought on or after January 1, 2026 in a custodial account and sold there.
The reporting phases are: Gross proceeds for sales from January 1, 2025; cost basis for covered assets bought from January 1, 2026 in a custodial account. Any covered coin sold in 2026 was held a year or less, so those sales are all short-term. Coins bought before 2026, or moved into the account from another platform or a wallet you control, are noncovered: the broker may leave basis blank, and your records supply it. On the return, these sales go in their own Form 8949 boxes, G through L, rather than the boxes used for stocks.
Lot selection has one more 2026 wrinkle: through December 31, 2026, you can identify the units you sell from a broker account, or record a standing order, in your own books and records rather than with the broker. Lots chosen that way control even if the broker's form lists different ones, so the 1099-DA may need adjusting. Box-by-box detail is in Form 1099-DA explained, and the rewards the form leaves out are covered in whether staking income is taxable.
What do Forms 1099-DIV, 1099-INT and 1099-OID report?
They report income taxable for 2026 whether or not you sold anything, split into boxes that are taxed at different rates.
- January payouts: a fund dividend declared in October, November or December and paid in January 2027 counts as received on December 31, 2026, under Publication 550, so it belongs on the 2026 form.
- Box 1b of Form 1099-DIV shows qualified dividends, taxed at long-term capital gains rates only if you also met the holding period; qualified vs ordinary dividends explains the test.
- Box 2a capital gain distributions are long-term however long you owned the fund.
- Box 3 is a return of capital: not taxed now, but it lowers your basis, and anything beyond basis is a capital gain.
- Box 7 foreign tax can be taken as a credit without Form 1116 if it totals $300 or less ($600 on a joint return) and all foreign income is passive and reported on a payee statement, per Publication 514.
- Box 3 of Form 1099-INT holds interest on Treasury bills, notes and bonds, which states cannot tax; see are T-bills taxable?, and the Treasury bill calculator to see what a bill pays.
- Form 1099-OID reports discount that builds up each year on long-term CDs, zero-coupon bonds and Treasury STRIPS, taxed before any cash is paid.
Worked example: Reading a fund's 2026 Form 1099-DIV
Jordan files single with $90,000 of taxable income. A fund's 1099-DIV shows $2,400 in box 1a, of which $1,800 is qualified in box 1b, plus $1,000 in box 2a, $200 in box 3 and $90 of foreign tax in box 7.
- Ordinary dividends that are not qualified: $2,400 − $1,800 = $600, taxed at 22%, or $132.
- Qualified dividends and capital gain distributions: $1,800 + $1,000 = $2,800, taxed at 15%, or $420.
- Foreign tax credit: $90, claimed without Form 1116. Net federal tax on the payouts: $132 + $420 − $90 = $462.
- The $200 return of capital is not taxed for 2026 but cuts the basis of Jordan's shares by $200.
Which retirement account forms matter for 2026 returns?
Form 1099-R reports every IRA or plan withdrawal, rollover and Roth conversion, while Form 5498 reports contributions and arrives after most people have filed.
Start with the code in box 7 of Form 1099-R: 7 marks a normal distribution, G a direct rollover, 1 an early distribution with no known exception and 2 an early one where an exception applies. The 2026 instructions add code Y for a qualified charitable distribution but make it optional this year, so a QCD may look like an ordinary taxable withdrawal. On the 2025 Form 1040, the full distribution went on line 4a, only the part that was not a QCD on line 4b, and a box on line 4c flagged the QCD.
A Roth conversion shows up twice: as a distribution on Form 1099-R and in box 3 of Form 5498. Conversions and nondeductible contributions also go on Form 8606, which tracks after-tax money; Roth vs traditional IRA covers the rules. The January 5498 statement gives the December 31, 2026 value and any 2027 RMD, but the contribution copy is not due until June 1, 2027, so for 2026 contributions made in early 2027, rely on your own records. Limits and deadlines are in IRA and 401(k) contribution limits, and the moves still open before December 31 are in year-end tax moves for investors.
What should you do if a corrected 1099 arrives?
Use the latest version, and if it arrives after you file and changes your tax, file an amended return on Form 1040-X.
Corrections are common for holders of mutual funds, ETFs and REITs. A fund may decide after year-end that part of a payout was a return of capital or a capital gain rather than a dividend, and the broker must then reissue the form, which is why Charles Schwab suggests that REIT and fund investors consider an extension. Waiting until March, or extending and paying the estimated balance by April 15, gives late corrections time to arrive. For a missing or wrong W-2 or 1099-R, IRS Topic 154 says to ask the payer, call the IRS if nothing arrives by the end of February and use Form 4852 as a substitute; a form that later differs from the estimate means filing Form 1040-X.
Payers send the same figures to the IRS. The wage and income transcript shows them, generally from the first week of February, but only for forms already filed. When a return and those figures disagree, the IRS sends a CP2000 notice proposing changes. It is not a bill, but it needs a reply by the date listed, and if you agree and have nothing else to report, no amended return is needed.
What mistakes do investors make most at tax time?
Most errors come from filing before every form arrives or from trusting what a form leaves out, such as missing basis or unreported wash sales.
- Filing before the February 16 broker statements, a March K-1 or a corrected form.
- Reporting zero basis for a box 5 lot or a noncovered coin.
- Missing a wash sale created by a purchase in another account.
- Paying tax twice on employee stock because the 1099-B basis leaves out W-2 income.
- Paying state tax on Treasury interest from box 3 of Form 1099-INT.
- Treating a QCD as a taxable withdrawal, or skipping Form 8606 after a conversion.
- Leaving off income that came with no form, such as staking rewards.
Line numbers above come from the 2025 return and may shift on the 2026 form. A tax professional is worth considering for a year with K-1s, employee stock or crypto.