For the 2026 filing cycle, the biggest Schedule K-1 tax changes are the permanent extension of the 20% qualified business income deduction under the One Big Beautiful Bill Act, an inflation-adjusted late-filing penalty of $260 per partner per month on Form 1065, and continued IRS enforcement of tax-basis capital account reporting. Calendar-year partnerships and S corporations still must issue K-1s by March 15, 2026, and individual returns incorporating that K-1 data are due April 15.
What Changed for the 2026 Filing Cycle
The 20% QBI Deduction Is Now Permanent
Section 199A’s 20% deduction on qualified business income was scheduled to sunset after 2025. The One Big Beautiful Bill Act, signed in mid-2025, made it permanent. If your K-1 reports income from a trade or business, you can potentially deduct up to 20% of that income without itemizing.
The full deduction is available if your 2026 taxable income falls below roughly $201,750 (single) or $403,500 (married filing jointly). Above those thresholds, the treatment splits. Owners of a specified service trade or business, such as law, medicine, consulting, or financial services, lose the deduction entirely once taxable income exceeds approximately $276,750 (single) or $553,500 (joint). Non-service businesses face limitations tied to W-2 wages paid and property held by the business, but the deduction doesn’t phase out completely at higher income levels.
You’ll calculate the deduction on Form 8995 or the more detailed Form 8995-A depending on your income. The K-1 itself won’t compute it for you.
Partnership Late-Filing Penalty: $260 Per Partner Per Month
A partnership that files Form 1065 late or leaves out required information owes $260 for each partner for each month (or partial month) the return remains unfiled, up to 12 months.1Internal Revenue Service. Internal Revenue Bulletin 2025-45 A 10-partner entity three months late owes $7,800. The penalty falls on the entity, not on individual partners, and smaller partnerships can request abatement for reasonable cause.2Office of the Law Revision Counsel. 26 USC 6698 – Failure to File Partnership Return
Tax-Basis Capital Account Reporting Continues
Partnerships must report each partner’s capital account using the tax-basis method. The IRS phased this in starting with 2020, and the 2025 Form 1065 instructions continue to require the transactional approach.3Internal Revenue Service. 2025 Instructions for Form 1065 The capital account shown on your K-1 now reflects your actual tax investment in the entity, which makes it easier for both you and the IRS to spot a distribution that exceeds basis and triggers gain.
Schedules K-2 and K-3 for International Items
Partnerships and S corporations with foreign income, foreign tax credits, or other international items report them on Schedules K-2 and K-3 rather than in freeform statements. The schedules standardize the information partners need to claim foreign tax credits or report foreign-source income.4Internal Revenue Service. Partnership Instructions for Schedules K-2 and K-3 (Form 1065) If your K-1 activity is purely domestic, these schedules won’t apply to you.
Form 7203 for S Corporation Shareholders
S corporation shareholders who claim a loss, receive a distribution, dispose of stock, or receive a loan repayment from the corporation must file Form 7203 with the individual return. It tracks your stock and debt basis year by year and controls how much of the S corporation’s losses and deductions you can actually use.5Internal Revenue Service. About Form 7203, S Corporation Shareholder Stock and Debt Basis Limitations
Electronic Filing Threshold Dropped to 10
The mandatory e-filing threshold fell from 250 information returns to 10.6Internal Revenue Service. Topic No. 801, Who Must File Information Returns Electronically The count aggregates across return types, so a small partnership that also issues a handful of 1099s can easily cross the line and be forced to e-file.7Internal Revenue Service. E-file Information Returns
K-1 Deadlines for the 2026 Season
Calendar-year partnerships and S corporations must file the entity return and issue K-1s by March 15, 2026.8Internal Revenue Service. Starting or Ending a Business 3 That leaves roughly a month to fold K-1 data into your Form 1040 before the April 15 individual deadline.
Many entities file Form 7004 for an automatic six-month extension, pushing the entity deadline to September 15.9Internal Revenue Service. About Form 7004, Application for Automatic Extension of Time to File Certain Business Income Tax, Information, and Other Returns If your K-1 won’t arrive until then, you’ll file your own extension using Form 4868.10Internal Revenue Service. About Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return An extension only delays filing, not payment. You still owe the tax by April 15, even if you’re estimating the K-1 numbers.
Estimated Taxes and 2026 Interest Rates
K-1 income creates estimated tax problems because the exact amount often isn’t known until after quarterly payment dates pass. You avoid an underpayment penalty by paying at least 90% of your current-year tax or 100% of prior-year tax (110% if prior-year AGI exceeded $150,000). If K-1 income arrives late in the year, the annualized income installment method on Form 2210 lets you weight payments toward the quarters when the income was actually earned, which can reduce or eliminate the penalty.11Internal Revenue Service. Instructions for Form 2210
Interest on underpayments changes quarterly. For 2026, the rate is 7% in Q1 and 6% in Q2.12Internal Revenue Service. Quarterly Interest Rates
If Your K-1 Is Late or Wrong
If April 15 comes and your K-1 hasn’t, estimate the income from prior years or preliminary statements, pay the estimated tax, and file for an extension. Missing the payment deadline triggers a failure-to-pay penalty of 0.5% of the unpaid balance per month, up to 25%.13Internal Revenue Service. Failure to Pay Penalty
If a K-1 looks wrong, you have two paths. Report consistently with the K-1 as issued and push the entity to send a corrected version. Or report the items the way you believe they should be reported and file Form 8082 to notify the IRS of the inconsistency.14Internal Revenue Service. About Form 8082, Notice of Inconsistent Treatment or Administrative Adjustment Request (AAR) Filing Form 8082 protects you from the accuracy-related penalty of 20% on any underpayment caused by negligence or a substantial understatement of income.15Internal Revenue Service. Accuracy-Related Penalty
Three Hurdles Before You Can Deduct a K-1 Loss
A K-1 showing a loss doesn’t automatically produce a deduction. Three filters apply in order, and the loss must clear all three.
Basis
You can deduct losses only up to your basis in the entity. Partnership basis includes capital contributions plus your share of entity liabilities. S corporation basis includes contributions and direct loans you made to the company, but not loans the company took from a bank. Losses over basis suspend and carry forward until basis increases.
At-Risk
Even with basis, deductible loss is capped at the amount you’re at risk. That includes money and property you contributed and amounts you personally borrowed for the activity. Nonrecourse financing where you carry no personal liability, and amounts protected by guarantees or stop-loss arrangements, generally don’t count.16Office of the Law Revision Counsel. 26 U.S. Code 465 – Deductions Limited to Amount at Risk Blocked losses carry forward.
Passive Activity
Losses that clear basis and at-risk still can’t offset wages, salary, or investment income unless you materially participated. Passive investors can only use K-1 losses against other passive income.17Office of the Law Revision Counsel. 26 U.S. Code 469 – Passive Activity Losses and Credits Limited Seven tests define material participation; the most common is working more than 500 hours in the activity during the year.18Internal Revenue Service. Publication 925, Passive Activity and At-Risk Rules Suspended passive losses release when you sell your entire interest in the activity.
Self-Employment and Net Investment Income Tax
General partners owe self-employment tax on their distributive share of ordinary partnership business income and on any guaranteed payments. Limited partners owe self-employment tax only on guaranteed payments for services, not on their profit share.19Internal Revenue Service. Entities 1 S corporation shareholders don’t pay self-employment tax on K-1 income, but they must take reasonable compensation as W-2 wages subject to payroll tax.
The 3.8% net investment income tax may also hit K-1 income treated as net investment income, including rental income, interest, dividends, capital gains, and passive business income, when modified AGI exceeds $200,000 (single), $250,000 (married filing jointly), or $125,000 (married filing separately).20Office of the Law Revision Counsel. 26 U.S. Code 1411 – Imposition of Tax The tax applies to the lesser of net investment income or the amount MAGI exceeds the threshold. Income from a business where you materially participate is generally exempt.
State Filing Won’t Track Federal
K-1 income doesn’t stop at the federal level. If the entity operates in a state where you don’t live, you may owe tax there on the share of income sourced to that state. Many states require the entity to withhold on income allocated to nonresident partners, with rates varying widely. Some states allow or require a composite return that pays state tax on behalf of nonresident owners so you don’t file a separate nonresident return, but not every state offers this and eligibility rules differ. If you’re an out-of-state owner, ask the entity’s preparer how the state piece is being handled before you file federally.