1. The 6,000 LB GVWR Rule: Bypassing Luxury Auto Depreciation Caps
Under standard IRS rules, ordinary passenger cars are subject to strict luxury automobile depreciation caps (limiting year-one write-offs to roughly $20,200). However, vehicles with a Gross Vehicle Weight Rating (GVWR) exceeding 6,000 pounds—such as the Mercedes-AMG G63 (7,055 lbs), Cadillac Escalade (7,600 lbs), Lamborghini Urus (6,327 lbs), and Tesla Cybertruck (9,169 lbs)—are classified as heavy transportation equipment, unlocking uncapped first-year bonus depreciation.
2. First-Year Cash Math for S-Corps and LLCs
When an S-Corp or LLC owner purchases a $185,000 G63 with 85% business usage, they create an immediate $157,250 tax deduction. At a top marginal combined federal and state tax rate of 46.3% (e.g. California or New York), this generates $72,836 in direct cash tax savings in Year 1, effectively reducing the net out-of-pocket acquisition cost to $112,164.
3. Compliance Audit Triggers: Mileage Logs & Recapture Risk
To defend against IRS audit scrutiny, business owners must maintain an irrefutable contemporaneous mileage log verifying that business use remains strictly above 50%. Dropping below 50% business use triggers severe depreciation recapture, converting previous tax write-offs back into ordinary income.
To model your exact vehicle write-off, bonus depreciation percentage, and net cash savings across different tax brackets, use the free Core-AI IRS Section 179 Heavy Vehicle Tax Calculator.