Originally Posted by Roger
Not quite sure of the question, my understanding is that AA is the exception among North American programmes. Certainly, my 2,700 AA miles
on a recent National rental had no miles tax.
Here is the excerpt from hertz.com partner section
For rentals in the U.S., Puerto Rico, and Canada when the renter chooses to receive miles in the American Airlines AAdvantage program the Frequent Flyer Surcharge will be calculated based on the Federal Excise Tax expense incurred by Hertz when it purchases miles from American Airlines. Under the Tax Relief Act of 1997, all companies that purchase Frequent Flyer miles from airlines must pay a 7.5% Excise Tax on the cost of those miles (on average, 6 cents per day).
It seems if you earn to AA miles for a rental you are charged about 6 cents per day. But then if an AA mile is 2cents or nowadays like 1 cent you are basically paying to get the miles and it is not a "loyalty" model any longer.