Estate Planning: The Basis-Step-Up Arbitrage

While the zero-basis boundary triggers immediate taxation for lifetime holders, keep holding if you are planning the estate. In a taxable brokerage account held until death, MLPs provide one of the cleanest tax-arbitrage strategies in the tax code:

Two structural shifts occur simultaneously at death:

Erase of Basis Reductions

Under IRC §1014, your heirs receive a stepped-up basis in the MLP units equal to the fair market value at the date of death. The entire decade of accumulated basis reductions (ROC distributions) is legally erased, along with any capital gains liability.

Exemption of Depreciation Recapture

On a lifetime sale, the accumulated depreciation deductions allocated to you over the holding period are recaptured and taxed at your maximum marginal ordinary income tax rate (up to 37%) instead of preferential capital gains rates. This depreciation recapture liability is entirely eliminated by the step-up at death.

The mechanism on a lifetime sale: §751 “hot assets.” Understand exactly how the ordinary-income bill arrives, because most investors expect a clean capital gain and get a surprise. Selling MLP units is selling a partnership interest, which would ordinarily produce capital gain — and Congress closed that door. IRC §751, “Unrealized receivables and inventory items” recharacterizes the portion of your sale proceeds attributable to the partnership’s “hot assets” as ordinary income, regardless of how long you held the units. For a midstream MLP the hot assets are overwhelmingly depreciation recapture: IRC §1245 on compressors, pumps, and processing equipment, IRC §1250 on structures, and IRC §1254, “Gain from disposition of interests in oil, gas, geothermal, or other mineral properties” on intangible drilling costs and depletion where the partnership owns producing assets.

The practical artifact is the Sales Schedule that accompanies your final K-1 in the year you sell. It states the cumulative basis adjustments and the §751 ordinary-income amount, which you report separately from the capital gain and disclose with a statement attached to your return. The arithmetic that catches people: on a position where the price merely tracked inflation, the §751 component can exceed the entire economic gain, so you can owe ordinary tax at 37% on a sale that made you almost nothing in real terms. This is the single strongest argument for the hold-until-death strategy, and the single strongest argument against treating MLP units as a position you will rebalance.

Consistently, the optimal strategy for direct MLP ownership is binary: buy high-quality midstream assets with the intent to hold them permanently, accept the administrative overhead, let the basis grind down to zero, and pass the units through your estate to execute a complete tax wipe. Trimming or rebalancing these positions in a taxable account during your lifetime destroys this arbitrage, triggering a massive ordinary income tax bill due to depreciation recapture.