Tax Code 1237L Explained: Holding Period, Lots, and Taxation

IRC Section 1237 is a safe harbor in the Internal Revenue Code that lets an individual landowner subdivide a single tract into lots and still report the gains as long-term capital gain, rather than having the IRS reclassify the whole operation as a dealer business taxed at ordinary income rates. Meet its conditions and the government cannot treat you as a real estate dealer solely because you subdivided and sold lots from land you held as an investment.

Who Can Use Section 1237

The section is available to individual taxpayers and most trusts. S corporations and partnerships can use it too, because the statute names only C corporations as excluded.¹

Two conditions attach to the land itself. The tract, or any part of it, cannot have been held primarily for sale to customers in a prior year. And in the same tax year you sell a subdivided lot, you cannot hold any other real property as a dealer.¹ The IRS looks at your overall pattern of real estate activity, so a taxpayer who regularly buys and flips other parcels in the same year will struggle to qualify.

How Long You Must Hold the Land

If you bought the land, you must own it for at least five continuous years before the first lot sale closes.¹ The five-year clock is waived entirely for land you inherited or received by devise.²

For gifted land, you tack the donor’s holding period onto your own under the general rules of Section 1223. The Treasury Regulations give a plain example: if the donor held the tract three years before gifting it, you only need to hold it two more to reach five.³

The Improvement Trap

This is where most Section 1237 claims fall apart. You lose the safe harbor for any lot affected by a “substantial improvement that substantially enhances the value” of the property.¹

The regulations provide a 10 percent safe harbor: an improvement that lifts a lot’s value by 10 percent or less is not considered a substantial increase. Going above 10 percent is not automatically fatal, but at that point the IRS weighs all the circumstances. Staying at or below 10 percent is the cleanest way to stay protected.³

The regulations also sort improvements by character. Shopping centers, residential or commercial buildings, hard-surface roads, and utility installations like sewer, water, gas, or electric lines are the risky ones. Surveying, filling, draining, leveling, clearing, temporary field offices, and minimum all-weather access roads (including gravel roads) generally are not treated as substantial.³

Improvements made by close family members, a corporation you control, an S corporation you’re a shareholder in, or a partnership you’re a partner in all count as yours.² So can improvements a buyer is contractually required to make. A contract that only restricts what a buyer may build is fine; a contract that obligates either party to build something substantial breaks the safe harbor.⁴

The 10-Year Exception for Necessary Improvements

If you’ve held the land at least 10 years, a narrow exception allows water, sewer, drainage facilities, or roads without breaking the safe harbor. All three conditions must be met:

You show the IRS that the lots would not have been marketable at prevailing local prices for similar building sites without the improvement.
The improvement is water, sewer, drainage facilities, or a road. Nothing else qualifies.
You elect to forgo adding the improvement cost to your basis in the lots or any other property you own, and you cannot deduct the cost as an expense.¹

The basis election is a real cost. You are permanently giving up the tax benefit of the improvement spending in exchange for keeping capital gains treatment on the lots. For a paved road or a sewer system, that money never reduces your taxable gain.

How the Gain Is Taxed

The math turns on how many lots you have already sold from the same tract.

The First Five Lots

For the first five lots or parcels sold from a tract, the entire gain is long-term capital gain, taxed at 0, 15, or 20 percent depending on income. In 2026, the 20 percent rate applies above $545,500 of taxable income for single filers and $613,700 for joint filers. Those rates are well below the ordinary income brackets that would apply to a dealer.

Sixth Lot and Beyond

Starting with the sixth lot sold from the same tract, and on every sale after that, 5 percent of the selling price is reclassified as ordinary income. The rest of the gain remains capital gain.¹ The top ordinary rate for 2026 is 37 percent.

Selling expenses (brokerage commissions, legal fees, and similar costs) follow a specific order. They first offset the 5 percent ordinary income portion. Anything left over reduces the amount realized on the sale, which lowers the capital gain.¹ That ordering keeps you from paying ordinary income tax on dollars that never reached your pocket.

Net Investment Income Tax

If your modified adjusted gross income is above $200,000 (single) or $250,000 (married filing jointly), a 3.8 percent net investment income tax applies to capital gains, including gains from real property.⁵ On the capital gain portion of a Section 1237 sale, that pushes the effective rate as high as 23.8 percent.

How the IRS Defines a Tract

The tract definition matters because the five-lot threshold is counted per tract. A tract is a single piece of real property, but two or more separate pieces are treated as one tract if they were ever contiguous while you owned them. Parcels separated only by a road, railroad, or stream are still contiguous.¹

Two or more contiguous lots sold to a single buyer in one transaction count as a single parcel toward the five. Exchanges count the same as sales, even when no gain is recognized on the exchange.³

There is also a reset. If you sell some lots and then make no further sales from the remaining land for five full years, the remainder is treated as a new tract, and the lot count starts over at zero.² The next five lots from that remainder qualify for full capital gains treatment again.

If You Don’t Qualify

Failing Section 1237 does not automatically make you a dealer. The safe harbor is a one-way shield: if you qualify, the IRS cannot use the subdivision itself against you. If you don’t qualify, the IRS still has to prove dealer status the ordinary way, based on all the facts and circumstances.³ Investors whose facts clearly show they were never dealers can still get capital gains treatment without relying on the section at all.

When the IRS does successfully classify someone as a dealer, the entire gain on each lot sale becomes ordinary income, with no 5 percent partial treatment. The gap between a 20 percent capital gains rate and a 37 percent ordinary rate on a large tract quickly runs into tens of thousands of dollars.

Records to Keep

Section 1237 puts the burden of proof on you. If you’re audited, gaps in your records are gaps in your defense.

Acquisition and holding period: the original deed, closing statement, or probate records showing when you acquired the property and how. If you’re tacking a donor’s holding period, get records of when the donor acquired the land.
No dealer status: evidence that no other real property you held was inventory in the same tax year. If you own other parcels, be ready to show they were investment or personal use.
Improvement records: before-and-after appraisals showing the value impact of any work done. For the 10-year exception, keep proof that the lots would not have sold without the improvement, plus documentation of your basis election.²
Lot sales log: a running count of lots sold from each tract, with dates, buyers, and prices. Track contiguous lots sold to one buyer separately, since those count as a single parcel.
Selling expenses: receipts and closing statements for commissions, legal fees, and other transaction costs, so you can allocate them properly against the ordinary income portion once you pass the fifth lot.

A professional appraisal before and after any improvement work is the single most useful piece of evidence you can keep. The 10 percent value-increase safe harbor is your clearest protection in a dispute, but only if you can prove the numbers.

1
Office of the Law Revision Counsel. 26 USC 1237 – Real Property Subdivided for Sale
2
Office of the Law Revision Counsel. 26 U.S. Code 1237 – Real Property Subdivided for Sale
3
eCFR. 26 CFR 1.1237-1 – Real Property Subdivided for Sale
4
eCFR. 26 CFR 1.1237-1 – Real Property Subdivided for Sale
5
Internal Revenue Service. Net Investment Income Tax