I’ve written before about what I call “hidden price increases,” where the manufacturer raises the invoice price paid by the dealer but leaves the sticker price that the public sees unchanged. Since the invoice price often determines the actual price you pay more than the sticker price does, car buyers end up paying more, but without realizing that anything has changed.

Audi recently applied such an increase across all of its models, to both base prices and options. For example, on an A6 4.2 sedan that lists for $56,300 (plus $775 destination), the invoice price went up from $51,861 to $52,361, an increase of $500. With options, invoice is now 93 percent of MSRP. It used to be 91 percent. So on a car with $5,000 in options the invoice price will now be another $100 higher, for a total increase of $600, even though the sticker remains the same.

It’s not hard to figure out why Audi is doing this: with the Euro worth more than $1.40, they may well be losing money in the United States lately. At a minimum they’re earning far less than they were when the dollar wasn’t so weak.

Why not just raise the sticker price? Probably because no one else is. The U.S. market remains high competitive, and this combined with the weakening dollar has made car prices much cheaper here than pretty much anywhere else in the world.