Do MLP investors receive a K-1 or a 1099?

MLP unitholders receive Schedule K-1 because the partnership passes profits and losses through to partners with no entity-level federal income tax. C-corporation midstream names such as Kinder Morgan and Williams issue Form 1099-DIV for dividends. The K-1 reports a share of the partnership's income rather than what was paid out, which is why much of an MLP distribution is a return of capital that cuts the cost basis instead of being taxed on receipt. It also arrives later than a 1099, often close enough to the deadline to force a filing extension.

Why is an MLP distribution not taxed like a dividend?

Because pipelines are depreciation-heavy, the taxable income allocated to a unitholder is normally far below the cash distributed. The excess is a return of capital: untaxed when received, but it reduces the cost basis of the units by the same amount, and once basis reaches zero further distributions are taxed as capital gains. The deferred tax comes due on sale, where the gain created by those basis reductions is recaptured under section 751 as ordinary income at the holder's marginal rate rather than as a long-term capital gain.

Why did Kinder Morgan convert from an MLP to a C-corp?

Kinder Morgan rolled up its affiliated MLPs into a single C-corporation in 2014, ending the multi-entity K-1 structure that complicated institutional and retail ownership. The company now files as a C-corp with 1099 dividend reporting and, from FY2025, emphasises free cash flow ($2,891M) rather than distributable cash flow. The roll-up is the sector's reference case for how structure changes tax forms, holder base, and which cash metric investors track.

Do C-corp midstream stocks trade at higher multiples than MLPs?

Published indices suggest yes. The Alerian MLP Infrastructure Index (AMZI) traded at 8.57× forward EV/EBITDA on 2027 consensus EBITDA as of 31 January 2026. The Alerian Midstream Energy Select Index (AMEI), which includes more C-corps, screened at 10.94× as of 28 February 2026. Some of that spread is investor base, retained cash and 1099 simplicity, but the two indices do not hold the same companies, so part of it is asset mix and geography rather than structure. Treat the gap as an upper bound on what the wrapper is worth.

Can a UK investor buy US MLPs?

In practice, rarely, and it is usually a poor idea when possible. MLP distributions to a non-US holder are treated as income effectively connected to a US business and withheld at the top US individual rate of 37%. Since January 2023, section 1446(f) has also required brokers to withhold 10% of the gross sale proceeds when a non-US person sells partnership units, whether the trade made money or lost it, and several retail brokers responded by closing publicly traded partnerships to non-US clients. The C-corp midstream names carry none of this: US dividends are withheld at 15% under the UK treaty with a W-8BEN on file, and a SIPP qualifies for full exemption.

MLP vs C-Corp: K-1s, Taxes and Who Owns Which

Educational analysis for professional use. This guide is not investment advice or a recommendation to buy or sell any security, and it is not personalised.

The Wrapper Sets Three Things

Two pipeline companies can own near-identical assets and hand the shareholder completely different tax outcomes. The wrapper drives the tax form first; holder base and index placement follow.

Master limited partnerships file Form 1065 and pay no federal income tax at the entity level. Profits and losses are allocated to unitholders instead, who receive a Schedule K-1: not a statement of what they were paid, but a statement of their share of the partnership’s income, deductions and depreciation. C-corporations pay tax on their own profits first and report dividends on Form 1099-DIV. Williams and Kinder Morgan are 1099 reporters; Enterprise Products Partners, Energy Transfer and MPLX are K-1 partnerships.

Midstream is thick with partnerships because the tax code lets it be. A publicly traded partnership only escapes corporate tax if at least 90% of its gross income comes from qualifying sources, and transporting, processing and storing oil and gas is on that list. Software is not, which is why MLPs cluster in energy and natural resources and barely exist anywhere else.

Skipping entity-level tax sounds like a straight win, and for the right holder it is. But the same mechanism that produces the saving produces a K-1, and a K-1 is unwelcome or unusable in a lot of accounts. Institutions want a single 1099. Retirement accounts trip over unrelated business taxable income. Non-US investors get most of the yield withheld before they see it. The post-2014 roll-up wave, led by Kinder Morgan collapsing its affiliated MLPs into one C-corp, gave up partnership tax efficiency to buy access to those holders.

FY2025 Structure Map

Company	Ticker	Structure	Tax form	Primary cash metric	Cap (Jun 2026)
Enterprise Products Partners	EPD	MLP	K-1	DCF $8,000M	~$80.8B
Energy Transfer	ET	MLP	K-1	Partner DCF $8,202M	~$65.6B
MPLX	MPLX	MLP (MPC-sponsored)	K-1	DCF $5,791M	~$57.6B
Kinder Morgan	KMI	C-corp	1099	FCF $2,891M	~$69.7B
Williams	WMB	C-corp	1099	AFFO $5,858M	~$87.5B
Enbridge	ENB	C-corp (CAD)	1099, Canadian WHT	DCF C$12,454M	~US$122.6B

MPLX adds a sponsor layer: Marathon Petroleum owns 63.7% of common units and 100% of the general partner, the entity that runs the partnership and appoints its board. That is still K-1 pass-through at the unit level, but assets sold down from the parent and customer concentration sit on top of partnership tax mechanics.

A 7% MLP Yield Is Not a 7% Dividend

In an MLP, the cash arriving in the account and the income being taxed are two different numbers, and the gap between them is where most of the confusion about MLP yields lives.

Pipelines are depreciation-heavy, so the taxable profit allocated to a unitholder is usually much smaller than the cash distributed. The excess is a return of capital. It is not taxed when received, but it reduces the cost basis of the units by the same amount. Buy a unit at $50, take $3 of distributions of which $2.40 is return of capital, and the basis drops to $47.60. Once basis reaches zero, further distributions are taxed as capital gains straight away.

The deferral is real and worth having. Nothing is forgiven, though, and the settlement is harsher than it looks. On sale, the slice of the gain created by those basis reductions is recaptured under section 751 and taxed as ordinary income at the holder’s marginal rate, not at the lower long-term capital gains rate. Only the remainder is a capital gain. A US investor who compounded a tax-deferred yield for ten years can find a large part of the exit taxed at the top income rate.

Two further consequences follow the K-1 rather than the cash.

Retirement accounts. Business income from the partnership reaches an IRA or 401(k) as unrelated business taxable income (UBTI), which is income from running an active trade rather than from passive investment. Tax-exempt accounts owe tax on it. Once gross UBTI across the account passes $1,000 in a year, the custodian must file Form 990-T and pay the bill out of the account itself. A wrapper bought to shelter income ends up filing a tax return.
State filings. The K-1 allocates income to every state the partnership operates in, which for a large MLP is a lot of them. That can create non-resident filing obligations wherever the allocation clears a state’s threshold. Most retail allocations are too small to trigger anything, but the K-1 also arrives later than a 1099, often close enough to the deadline to force an extension.

None of this makes the MLP the worse structure. It makes it a structure that only pays off in the right account: a US taxable one, held long enough for the deferral to compound, by someone content to file the paperwork.

What This Means for a UK Investor

The MLP tax advantage is built for a US taxpayer and does not travel.

Distributions to a non-US holder are treated as income effectively connected to a US business, so tax is withheld at the top US individual rate of 37% before the cash arrives. Then, since January 2023, section 1446(f) has required brokers to withhold 10% of the gross proceeds when a non-US person sells partnership units, whether the trade made money or lost it. Sell $10,000 of units at a loss and $1,000 is still withheld, reclaimable only by filing a US return. Several retail brokers reacted by refusing to open positions in publicly traded partnerships for non-US clients at all.

The C-corps carry none of that. Kinder Morgan and Williams are ordinary US shares: 30% withholding on dividends falls to 15% under the UK treaty once a W-8BEN is on file, and a SIPP qualifies for full exemption because the IRS recognises it as a pension scheme. Enbridge is a Canadian corporation, so the withholding is Canadian rather than US, again 15% by treaty.

Put numbers on it. EPD’s ~5.9% distribution yield arrives as roughly 3.7% after 37% withholding, with the 10% on gross proceeds still waiting at the exit. Whatever yield advantage the partnerships show on screen is largely an advantage for the people who can file a US tax return.

The Multiple Gap: AMZI vs AMEI

Pure-MLP indices screen lower than indices that include more C-corps. February 2026 Alerian data:

Index	Forward EV/EBITDA	Basis	As-of
AMZI (MLP infrastructure)	8.57×	2027 consensus EBITDA	31 Jan 2026
AMEI (midstream energy select)	10.94×	2027 consensus EBITDA	28 Feb 2026
Wells Fargo midstream median	9.0× trailing	Universe median; 10-yr avg 9.3×	31 Mar 2026

The illustrative working band for large-cap midstream sits at ~8–10×, anchored between AMZI and AMEI. C-corp-heavy names tend toward the top of that band: 1099 reporting pulls in institutions, and retained cash supports re-rating without payout drag.

Resist reading the whole gap as a tax effect. The two indices do not hold the same companies. AMEI reaches into Canadian corporates and a different asset mix, so part of the spread is what each index owns rather than how each is taxed. Structure is one input into the difference and it is not separable from the others with two index prints.

Worked Example: Same Sector, Different Screen

Take one illustrative $6,000M of adjusted EBITDA and price it off each index anchor:

Entity type	EBITDA ($M)	Multiple anchor	Implied EV ($M)
MLP-style (AMZI)	6,000	8.57×	51,420
C-corp-heavy (AMEI)	6,000	10.94×	65,640

Treat the $14,220M gap as the outer bound of what the wrapper might be worth, not a measurement of it. Leverage, coverage, contract quality and the differing constituent lists all sit inside that number. What survives the caveats is the direction and its rough size, which is enough to explain why the C-corp roll-ups were pitched on re-rating as much as on tax simplicity, and enough to tell you that comparing an MLP’s multiple to a blended midstream index is not a like-for-like screen.

See EV/EBITDA by midstream asset type for the full multiple framework; DCF vs FCF for the cash metric that pairs with MLP distributions.

Who Tends to Own Which

This is analytical framing, not tax advice. Consult a tax professional before placing midstream equities in IRAs, pensions, or taxable accounts.

K-1 MLPs (EPD, ET, MPLX). US taxable accounts, held by income investors who want the deferral and will do the filing to get it. Computed FY2025 yields: EPD ~5.9%, ET ~6.9%, MPLX ~7.2%, inside the ~5–8% convention band. Read those as pre-settlement figures. For a US holder much of the yield is deferred rather than free; for a UK holder more than a third of it never arrives.

1099 C-corps (KMI, WMB, ENB). Institutions and dividend-growth accounts that cannot process K-1s. KMI emphasises FCF; its 2026 budgeted EBDA is 96% take-or-pay, fee-based or hedged, of which 65% is take-or-pay. WMB pairs >90% fee-based earnings with Transco expansion (~7.1 Bcf/d in execution, ~14.3 Bcf/d additional 2027–2033). ENB reports in CAD: 98% low-risk EBITDA, Mainline throughput 3.1 MMbpd.

The 2014 KMI roll-up is the cautionary flip side. Unitholders who exchanged K-1 partnership interests for C-corp shares took a taxable event to gain 1099 simplicity and, management hoped, a higher multiple. Not every MLP conversion re-rated; tax often crystallises before any multiple benefit shows up.

What Structure Does Not Tell You

Wrapper does not replace contract quality or distribution coverage. ET is a K-1 MLP with $15,984M consolidated EBITDA and computed coverage ~1.80×; MPLX is a K-1 at the 1.4× comfort floor. KMI is a C-corp with no filed DCF but 65% take-or-pay on its 2026 budget.

Structure also does not map to commodity exposure. Fee-based shares differ by denominator: EPD cites 82% of gross operating margin; ET ~90% of adjusted EBITDA; WMB >90% of fee-based earnings. A C-corp label does not mean commodity-beta. An MLP label does not mean safe payout.

And neither wrapper is better in the abstract. The MLP wins for a US taxable holder who will hold for years and file the K-1; the C-corp wins for a pension, an institution, an index fund and almost every investor outside the United States. The same partnership is the more tax-efficient structure and the less ownable one, depending entirely on who is asking.

When screening midstream, sort by structure first (K-1 vs 1099), then apply the cash metric that matches (DCF, AFFO, or FCF), then coverage for MLPs, then leverage. Skipping the first step is how E&P EV/DACF screens get misapplied to toll-road balance sheets.