Schedule K-1 is the IRS form issued by partnerships, S-corporations, estates, and trusts to report each owner's or beneficiary's share of pass-through income, deductions, credits, and other tax items — which the recipient then reports on their personal tax return.
Schedule K-1 is the reporting mechanism for pass-through taxation — the fundamental principle that partnerships, S-corporations, LLCs taxed as partnerships, and trust/estate income is not taxed at the entity level but passes through to individual owners and is reported on their personal returns. There are three versions: Form 1065 Schedule K-1 (for partnership and multi-member LLC partners, irs.gov/forms-pubs/about-schedule-k-1-form-1065), Form 1120-S Schedule K-1 (for S-corporation shareholders, irs.gov/forms-pubs/about-schedule-k-1-form-1120-s), and Form 1041 Schedule K-1 (for estate and trust beneficiaries). K-1 reports a partner's or shareholder's allocable share of: ordinary business income or loss (Box 1), rental income, royalties (Box 2–3), interest income (Box 5), dividends (Box 6), capital gains (Box 8–9), Section 179 deductions (Box 12), charitable contributions (Box 13), self-employment earnings (Box 14 for partnerships), credits (Box 15), AMT items (Box 17 for partnerships / Box 15 for S-corps), and other items that retain their character when flowing to the partner's return. For business owners seeking financing: lenders use K-1s as primary income documentation for partners and S-corp shareholders. Lenders typically require 2 years of K-1s plus the entity's Form 1065 or 1120-S return and analyze ordinary income (adjusting for non-cash items like depreciation). The IRS requires partnerships to issue K-1s to all partners by the due date of Form 1065 (March 15, or September 15 with extension) — late K-1s delay partners' ability to file their personal returns. Instructions at irs.gov/pub/irs-pdf/i1065sk1.pdf.
It depends on the entity type and the partner's role. General partners in a partnership (and LLC members treated as general partners) pay SE tax on their distributive share of ordinary business income under IRC §1402. Limited partners generally do not pay SE tax on their distributive share (IRC §1402(a)(13)). S-corporation shareholder K-1 income (box 1 ordinary income) is NOT subject to SE tax — only the W-2 salary the S-corp pays the shareholder is subject to FICA. This SE tax distinction is a primary driver of S-corp election decisions (irs.gov/forms-pubs/about-schedule-k-1-form-1120-s).
You'll need to file an amended return (Form 1040-X) to include the K-1 income, deductions, and credits. Late K-1s are common — partnerships frequently extend Form 1065 to September 15, which means partners may not receive K-1s until October. If you file your 1040 before receiving a K-1, estimate the income and file an extension. The IRS matches K-1 data filed on Form 1065 against individual returns — unreported K-1 income triggers IRS notices (irs.gov/forms-pubs/about-schedule-k-1-form-1065).
Lenders generally require 2 years of K-1s plus the underlying partnership (1065) or S-corp (1120-S) return. Qualifying income is typically the 2-year average of Box 1 ordinary income, adjusted upward for non-cash deductions (depreciation, depletion) and downward for non-recurring income. Some lenders apply a 'business use of home' analysis and require the business to show sufficient retained earnings or liquidity. For SBA loans, SBA SOP 50 10 governs income calculation from K-1s (sba.gov/sites/default/files/2024-06/SOP-50-10-7-FINAL.pdf).