If you don’t own a Hummer yet, you had better move fast.

The absurd tax break the federal government offers on extra-large SUVs – call it a “humdinger” of a loophole – expires at the end of the year.

The tax break was originally intended to help people like the local plumber buy a truck for work. But Congress never expected that Detroit would one day convince Americans to buy “trucks” as passenger cars.

In 2003, however, the Bush administration pushed through a generous expansion of the 1996 write-off, making huge SUVs available to small-business owners at a fraction of the normal cost.

The tax break works like this, according to an article originally appearing in USA Today: A business owner purchases a $45,000 luxury SUV. He can write off $24,000 as accelerated depreciation, then depreciate the remaining $21,000 under a five-year schedule, $4,200 of that in the first year. So a vehicle with a $45,000 price tag receives a $28,200 write-off in the first year.

The government’s incentive for buying a fuel-efficient hybrid vehicle, meanwhile, is a relatively paltry $4,000.

Despite high gas prices, automakers are gearing up for a surge in SUV sales before this illogical tax break expires. It is, apparently, a deal just too good to pass up.