New Mexico capital gains tax (2026): selling a business, real estate or farm

The 2025 rewrite: a business seller's deduction, not an investor's

House Bill 252, enacted in 2024, rewrote Section 7-2-34 NMSA 1978 for tax years beginning in 2025. A taxpayer now deducts the greater of (1) net capital gain up to $2,500, or (2) 40% of up to $1,000,000 of net capital gain from the sale of a business that is allocated or apportioned to New Mexico under Section 7-2-11 (HB 252 enrolled text; 2025 PIT-ADJ instructions, line 16). The old deduction reached any net capital gain, so stock, land and rental sellers lost most of their break in the rewrite.

For a qualifying business sale the arithmetic is simple: 40% of the first $1 million is a $400,000 deduction, which at the 5.9% top rate (2026) is worth up to $23,600 of state tax per year the cap applies. Every dollar of gain past $1 million is taxed at the full rate. In the worked example the business seller owes $118,000 and the rental seller $141,453, a gap of $23,453 on identical gains.

What counts as the sale of a business

The statute does not define "sale of a business", and the 2025 instructions repeat the statutory words without examples. Points to settle with your CPA before you sign:

• Asset sale or stock sale. Both produce capital gain from disposing of a business; whether the Taxation and Revenue Department reads the phrase that broadly is not yet addressed in published guidance we found.
• Real estate inside the deal. A building sold with the operating company is part of a business sale in common usage. A stand-alone rental or raw land, as modeled in the second run, is treated by our engine as not qualifying.
• Allocated to New Mexico. Only gain allocated or apportioned to New Mexico counts, so a multistate company's gain is cut to the New Mexico share first.
• Ordinary pieces. Depreciation recapture, inventory and a non-compete are ordinary income, not net capital gain, so they get no deduction. A careful purchase price allocation decides how much of the price is eligible.

Short-term gain gets nothing

New Mexico borrows the federal definition: net capital gain is the excess of net long-term capital gain over net short-term capital loss under IRC 1222(11), and the PIT-ADJ instructions state that it does not include short-term capital gain (2025). An owner who formed a new entity or bought out a partner within the last year should check the holding period on every piece before closing. Federal law also taxes that gain at ordinary rates, so the cost doubles.

Spreading a business gain: does the $1 million cap reset?

The deduction is computed for "the taxable year for which the deduction is being claimed" (NMSA 7-2-34 as amended in 2024). Read literally, the $1 million cap applies to the gain reported in each year. Under a Section 453 installment sale, gain is reported as payments arrive (IRC 453), and New Mexico starts from federal AGI, so a $2.4 million business gain collected over three years puts $800,000 into each year and every dollar would sit under the cap.

Our engine applies the cap per year, and the three-year run shows $84,960 of New Mexico tax versus $118,000 in a single year, with federal tax also lower. The Department has not published guidance on installment reporting of the business deduction that we could find, so treat the per-year reading as a position for your CPA to confirm, not a settled rule. The buyer still has to pay, so the note needs a down payment, a lien on the business assets and a personal guarantee from the buyer's owners.

Nonresidents, real property and oil and gas

A seller living elsewhere still owes New Mexico on gain from real property located in the state: PIT-B line 5 allocates it to New Mexico in full (2025 PIT-B instructions). The same schedule sources rents and royalties from New Mexico oil and gas interests to the state, which matters for ranch and mineral owners in the Permian. A nonresident selling a New Mexico business gets the 40% deduction only on the gain apportioned to New Mexico. We found no New Mexico withholding on nonresident real estate sales comparable to other states' closing payments; the tax is settled on the PIT-1 return.

Rates and the federal layer

New Mexico's six brackets run from 1.5% to 5.9%, with 5.9% applying above $315,000 of taxable income for joint filers and $210,000 for single filers, set by HB 252 for tax years 2025 and later without inflation indexing. Married filing separately spouses each take half of the joint capital gain deduction (2025 PIT-ADJ). Federally, long-term gain is taxed at 0%, 15% or 20%, the 20% rate beginning at $613,700 of joint taxable income (Rev. Proc. 2025-32, 2026); see the capital gains overview, the business sale page and the state-by-state table. To model your own sale, get the Big Sale Tax Analysis.

Run your own numbers

Frequently asked questions