Partnership Taxes 101: Form 1065 & K-1 Basics

If you own a piece of a partnership or a multi-member LLC taxed as one, tax season brings a document you cannot ignore: Schedule K-1. Unlike a W-2 or a 1099, a K-1 does not tell you what to enter on one line — it hands you a dozen or more numbers, each governed by its own rules about whether and when you can actually use it. Here is what a partnership return produces, and what your K-1 actually means.

This is general information, not individual tax advice — the right treatment depends on your specific situation.

Who Files a Partnership Return

A partnership itself does not pay federal income tax. Instead, it files Form 1065 to report the entity's income, deductions, gains, and losses, and then issues a Schedule K-1 to every partner showing that partner's share of each item. The partners report those amounts on their own returns and pay tax individually — which is why partnerships are called pass-through entities. Multi-member LLCs that have not elected corporate taxation are treated as partnerships by default and follow the same Form 1065 and K-1 process.

The K-1: What It Actually Reports

A Schedule K-1 breaks your share of the partnership's results into separate categories — ordinary business income, rental income, interest, dividends, capital gains, Section 179 deductions, and more — because each category can be taxed differently or subject to different limitations on your personal return. This is also why a K-1 usually arrives later than a W-2: the partnership must first close its own books and complete its own return before it can calculate what belongs to each partner.

Basis: The Number That Limits Your Losses

The single most important number a K-1 does not show you is your basis in the partnership — and it is the first gate any loss has to pass through. You can generally only deduct your share of a partnership loss up to the amount of your adjusted basis in the partnership at year-end; a loss beyond that is suspended and carried forward, not lost, but also not usable until your basis grows enough to absorb it. Basis tracking is an ongoing, cumulative calculation across every year you hold the interest, which is exactly why it is so often mishandled — it is not printed anywhere on the K-1 itself, and it is easy to lose track of if no one has been maintaining it consistently.

At-Risk and Passive Activity: Two More Gates

Clearing the basis limitation does not automatically mean a loss is deductible. Next comes the at-risk limitation, which caps your deductible loss at the amount you could actually lose in the activity — generally your cash and property contributed plus certain borrowed amounts you are personally liable for. After that comes the passive activity limitation: if you do not materially participate in the business, your losses may only offset passive income, with any excess carried forward until you have passive income to absorb it or dispose of the interest entirely. The K-1 reports the raw numbers; applying basis, at-risk, and passive rules in the correct order is the taxpayer's job, not the partnership's.

Guaranteed Payments vs. Distributions

Partners are not employees, so they do not receive a W-2 salary from the partnership. Instead, a partner who performs services may receive a guaranteed payment — compensation that is deductible to the partnership and taxable to the partner regardless of the partnership's overall profitability. This is different from a distribution, which is simply a withdrawal of the partner's own capital or share of profits and is generally not itself a separate taxable event, though it can trigger gain if it exceeds the partner's basis. Confusing the two is a common and costly mistake, since guaranteed payments are also subject to self-employment tax in ways ordinary distributions are not.

When K-1s Arrive Late (and Why)

Partnership returns are due earlier than individual returns specifically so that partners have their K-1s in hand before their own filing deadline — but complex partnerships with tiered ownership, foreign partners, or late-closing books routinely file on extension, and K-1s can arrive well into the fall. If you are still waiting on a K-1 close to your own filing deadline, the right move is almost always to extend your personal return rather than guess at the numbers and amend later.

How VarStan Helps

Partnership taxation is one of the areas where the return itself is only half the work — the basis schedule that sits behind it has to be maintained year over year, correctly, by someone who is actually tracking it. We prepare partnership returns and K-1s for our clients, and just as importantly, we maintain the basis and at-risk calculations so a loss carryforward does not quietly get lost between preparers. If your partnership interest has never had its basis tracked formally, that is worth fixing before the next K-1 arrives.