M&A Advisory in Idaho

Idaho HB 40, signed March 6, 2025 and applied retroactively to January 1, 2025, lowered both the individual flat income tax rate and the corporate income tax rate from 5.695% to 5.3% (Idaho Code §63-3024). The reduced rate applies to the full 2025 tax year and remains in effect for 2026. Idaho's Affected Business Entity (ABE) election under HB 317 (2021), codified at Idaho Code §63-3026B, allows S corporations and partnerships to elect to pay Idaho income tax at the entity level at the 5.3% rate as a federal SALT-cap workaround — but PTEs that make the ABE election cannot claim the Idaho capital gains deduction on the sale of Idaho property.

Idaho allows individual taxpayers a 60% deduction of net capital gain income from the sale of qualifying Idaho-situs property, claimed on Form CG. Qualifying property includes Idaho real property held ≥12 months, tangible personal property used in Idaho ≥12 months by a revenue-producing enterprise, cattle/horses held ≥24 months, other breeding livestock held ≥12 months, and timber grown in Idaho ≥24 months. After the deduction, the effective Idaho rate on qualifying gain is roughly 2.12% (5.3% × 40%) — one of the lowest effective state capital-gains rates on private business sales in the U.S. ABE-electing entities cannot pass the deduction through to owners.

Idaho conforms to the IRC on a static basis — updated by HB 559 (February 2026) to conform to most OBBBA provisions for tax year 2025. Idaho conforms to §1202 at both the individual (Idaho Code §63-3011B) and corporate (§63-3004) levels. The federal QSBS exclusion (up to 100% / $10M or 10× basis for pre-OBBBA stock; up to $15M for QSBS acquired after July 4, 2025) flows through to Idaho taxable income. Founders of qualifying Idaho C-corps can exit with effectively zero state tax on excluded QSBS gains — a particularly powerful tool in the Boise tech and semiconductor ecosystem.

Idaho has no state estate tax, no inheritance tax, and no gift tax for 2025-2026. The Idaho estate tax expired for deaths after January 1, 2005. Idaho residents are subject only to the federal estate/gift tax, with the OBBBA-enhanced exemption of $15 million per individual / $30 million per married couple beginning January 1, 2026 (indexed). Combined with stepped-up basis at death, this makes Idaho an attractive domicile for owners executing pre-sale gifting strategies (IDGTs, SLATs, GRATs) prior to a business sale.

Idaho imposes a 6% state sales/use tax (Idaho Code §63-3619), with limited resort-city add-ons (typically 1-3% in Sun Valley/Ketchum, Stanley, McCall). In an asset sale, transfers of tangible personal property are taxable unless an occasional/isolated sale or manufacturing/agricultural production exemption applies (§63-3622D for manufacturing equipment, §63-3622W for irrigation equipment). Successor liability under Idaho Code §63-3628 requires a buyer to withhold from the purchase price any unpaid sales/use tax until the seller produces a Successors' Liability Clearance Letter from the Idaho State Tax Commission (issued within 30-60 days).

The Idaho TRI under Idaho Code §67-4737 and IDAPA 28.04.01 is a post-performance, refundable tax credit of up to 30% for up to 15 years on new corporate income tax, sales tax, and payroll-withholding tax generated by a qualifying project. Eligibility requires at least 20 new full-time jobs in rural areas or 50 new jobs in urban areas (Boise, Meridian, Nampa, Idaho Falls), wages at or above the county average, and a meaningful community contribution. Idaho also offers a 3% Investment Tax Credit, a 2.5% Real Property Improvement Tax Credit, and the Idaho Opportunity Fund grant — all of which can be quantified as buyer-side value drivers in the CIM and diligence process.