An investor buys 300 units of an energy pipeline partnership because the yield looks irresistible — 7% or 8%, paid quarterly, far above what any dividend stock or bond offers. The checks arrive on schedule. Then March comes, and instead of a tidy 1099-DIV, a thick package shows up labeled Schedule K-1. It has boxes for income earned in seven states, a footnote about "ordinary gain under Section 751," and a warning that the units should never have been held in an IRA.
What looked like a simple high-yield investment turns out to be a tax compliance project. Master Limited Partnerships (MLPs) are not bad investments, but they are taxed unlike anything else a retail investor is likely to own. Understanding the K-1 before you buy — not the following April — is the difference between a smooth holding period and an expensive surprise.
This guide walks through the four issues that catch MLP investors off guard: how distributions and basis actually work, why an IRA is the worst place to put one, what happens to your tax bill when you sell, and which states expect a return from you.
What an MLP Actually Is
A Master Limited Partnership is a publicly traded business — usually in energy infrastructure like pipelines, storage terminals, or natural gas processing — that is organized as a partnership rather than a corporation. Familiar names include Enterprise Products Partners and Energy Transfer.
The structure matters because partnerships do not pay corporate income tax. Instead, every item of income, deduction, gain, and loss "passes through" to the unitholders in proportion to their ownership. When you buy units, you are not a shareholder receiving dividends. You are a limited partner earning a share of an operating business. That single fact drives everything that follows.
Because the income passes through, the partnership cannot send you a 1099-DIV. It must send you a Schedule K-1 (Form 1065), which reports your allocated share of the partnership's results — whether or not any cash changed hands.
Issue 1: Distributions Are Not Dividends — They Reduce Your Basis
The most useful thing to understand about MLPs is the gap between the cash you receive and the income you are taxed on.
When an MLP pays you a quarterly distribution, that cash is generally not immediately taxable. The partnership generates large depreciation deductions on its pipelines and facilities, which often shrink its taxable income to a small fraction of the cash it distributes. So most of your distribution is treated as a return of capital.
A return of capital is not free money — it is a reduction of your cost basis. Here is how your basis moves over a holding period:
- Starting basis: what you paid for the units.
- Plus your share of partnership income (Box 1 and related boxes on the K-1).
- Minus your share of deductions, especially depreciation.
- Minus the cash distributions you received.
A simple example. You buy 300 units for $9,000. Over the next year you receive $640 in cash distributions, but your K-1 allocates you only $90 of net taxable income. Your basis adjusts roughly like this:
Starting basis $9,000
+ Allocated income $90
- Cash distributions $640
= Adjusted basis $8,450You received $640 in cash but reported only $90 of taxable income for the year. The other $550 was tax-deferred — it quietly lowered your basis instead.
This is the appeal of MLPs: the distributions are largely tax-deferred while you hold. But "deferred" is the key word. That deferral does not vanish — it gets settled when you sell. Two further wrinkles:
- Basis can reach zero. If your cumulative distributions exceed your basis, the excess is no longer tax-deferred — it becomes a taxable capital gain in the year you receive it, even though you still own the units.
- Your broker has the wrong number. Brokers compute the cost basis on your 1099-B from your purchase price. They never see your K-1 and never adjust for distributions, income, or depreciation. The 1099-B basis for an MLP is almost always incorrect, and the K-1 sales schedule is what you must actually use. More on this below.
Because of this, tracking the true adjusted basis of an MLP yourself — year by year — is not optional. Keep every K-1.
Issue 2: Never Hold an MLP in an IRA (Without Doing the Math)
The single most common and most expensive MLP mistake is buying units inside a traditional or Roth IRA, assuming the retirement account shelters everything. It does not.
Retirement accounts are tax-exempt, but the exemption has a deliberate exception: Unrelated Business Taxable Income (UBTI). Congress did not want tax-exempt accounts running active businesses tax-free and out-competing taxable ones. So when a tax-exempt account earns income from an operating business unrelated to its purpose, that income is taxable to the account itself.
An MLP is an operating business. Your IRA, as a limited partner, is treated as earning its share of pipeline income — and that share is UBTI.
The $1,000 cushion. Each retirement account gets a $1,000 specific deduction under Internal Revenue Code Section 512(b)(12). If your total UBTI from all MLPs across all retirement accounts at the same custodian stays at or below $1,000 for the year, no tax is due and no return is required. During normal holding years, MLP Box 1 income is often small or even negative, so many investors never breach $1,000 — which is exactly why the trap feels invisible.
When it triggers. Once UBTI exceeds $1,000, the IRA must obtain its own Employer Identification Number and file Form 990-T, and the tax is computed at trust tax rates — a compressed schedule that reaches the top 37% bracket at roughly $16,000 of income in 2026. The tax is paid out of the IRA. Custodians typically charge $200–$500 to prepare the 990-T on top of the tax itself.
Worst of all, you get the downside without the upside: in a Roth IRA, the UBTI tax is paid even though qualified withdrawals would have been tax-free anyway. You converted a tax-free account into a taxable one for that income.
The cleanest fix for most investors who want MLP exposure in a retirement account is to hold an MLP-focused ETF or fund structured as a corporation instead of the MLPs directly. Those funds issue an ordinary 1099 and generate no UBTI — at the cost of a layer of fund-level tax. Holding the partnership units themselves belongs in a taxable account.
Issue 3: Selling Triggers Section 751 "Recapture" — Ordinary Income at the Worst Rate
Here is where the deferred taxes from Issue 1 come due. When you sell MLP units, you would expect a simple capital gain: sale price minus basis. It is not that simple.
All those years of depreciation deductions lowered your basis and sheltered your distributions. The IRS recaptures that benefit at sale. Under Section 751 of the tax code, the portion of your gain attributable to "hot assets" — primarily depreciation recapture — is taxed as ordinary income, not as long-term capital gain.
This matters because ordinary rates run up to 37%, while long-term capital gains top out at 20%. A chunk of what feels like a capital gain is taxed at the higher rate.
The final K-1 you receive in your sale year includes a sales schedule with two critical numbers: a cumulative basis adjustment (so you can compute your true basis) and an ordinary gain / Section 751 amount. The total gain splits into an ordinary-income piece and a capital-gain piece. You report the ordinary piece on Form 4797 and the rest on Form 8949 and Schedule D.
The double-tax trap. Because your broker's 1099-B shows the wrong (unadjusted) basis, if you simply enter the 1099-B figures you will overstate your basis, then also report the ordinary income from the K-1 — taxing part of the gain twice, or in the wrong place. You must reconcile the 1099-B against the K-1 sales schedule and adjust the cost basis with code B in column (f) of Form 8949. This is the same reconciliation discipline that brokerage cost-basis reporting requires generally — the K-1 is simply the authoritative record for an MLP.
The IRA version of this trap. Recall Issue 2. An investor can hold MLP units in an IRA for years, watch UBTI stay under $1,000, and never file a 990-T — then sell. The Section 751 ordinary income on the final K-1 is itself UBTI. A position that never triggered a filing in eight years can produce several thousand dollars of UBTI in one transaction, generating tax at trust rates plus custodian fees. The sale is what springs the trap.
One genuine bright spot, and only in a taxable account: if you hold the units until death, your heirs receive a stepped-up basis equal to the fair market value on the date of death. That step-up wipes out all the accumulated Section 751 recapture. Inherited IRAs get no such step-up — another reason the partnership units belong in a taxable account.
Issue 4: You May Owe Tax in States You Have Never Visited
An MLP operates pipelines and facilities physically located in many states. Each of those states can tax your proportional share of the income earned within its borders — even if you have never set foot there.
Your K-1 includes a state allocation schedule breaking your income down state by state. In a typical holding year the amounts are tiny — a few dollars of income sourced to each of a dozen states — and usually fall below each state's filing threshold. Several major MLP states (Texas and Wyoming, for example) have no personal income tax at all.
Two things keep this manageable:
- Filing thresholds. Most states only require a nonresident return once your state-sourced income exceeds a dollar threshold. During holding years, MLP allocations rarely clear those thresholds.
- Composite returns. Many MLPs file a composite return on behalf of nonresident unitholders — the partnership calculates and remits the state tax for you, and you generally do not file separately in that state.
Between those two factors, most retail MLP investors file zero to three nonresident state returns during their holding years, beyond their home state.
The sale year is different. When you sell, the gain is allocated across all the operating states at once. States where you reported $15 of income annually may suddenly show several hundred dollars of gain. Multiple states can cross their filing thresholds simultaneously, and the sale year can require a handful of nonresident returns. Budget time — and possibly a preparer — for the year you exit.
Why Careful Records Make MLPs Manageable
Notice the common thread across all four issues: the K-1 is the source of truth, and nothing else is. Your broker's 1099-B is wrong on basis. Your account statement shows cash, not taxable income. The deferred tax from year one only becomes visible at sale, years later, when you need every K-1 you ever received.
This is exactly the kind of multi-year, multi-document tracking that plain-text accounting handles well. By recording each year's K-1 — allocated income, distributions, depreciation, the running basis adjustment — in a ledger you control, you build an unbroken audit trail. When you finally sell, your true adjusted basis is a number you can verify, not a figure you have to reconstruct from a decade of statements. The ordinary-income split, the state allocations, the UBTI tally for any retirement account — all of it lives in one place you can search and prove.
The investors who find MLPs painless are simply the ones who never let the paperwork pile up.
Keep Your Investment Records Audit-Ready from Day One
MLP units reward patient investors, but only those who treat the K-1 as a yearly bookkeeping task rather than an April surprise. Tracking adjusted basis, distributions, and recapture across many years is far easier when your records are transparent and under your own control. Beancount.io provides plain-text accounting that gives you complete visibility and ownership of your financial data — no black boxes, no vendor lock-in, and a version-controlled history you can audit at any time. Get started for free and see why developers and finance professionals are switching to plain-text accounting.
This article is general information, not tax advice. MLP taxation is genuinely complex — consult a qualified tax professional about your specific situation before buying or selling units.