Volkswagen's diesel models have lost their value in the auction lanes at a much sharper rate than comparable gasoline models since revelations came to light that the company had included a software cheat in the vehicles to beat emissions tests, according to Black Book.

Volkswagen's Golf TDI, Jetta TDI, Beetle TDI, and Passat TDI have in most cases recorded a depreciation rate more than double of the comparable gasoline models since Sept. 18. The Golf TDI fared the best with a 5% depreciation rate compared to the gasoline Golf's 3.5% depreciation.

The Passat TDI, which is the top fleet seller, has depreciated 7.9% compared to the 2.3% depreciation of the gasoline Passat.

The Jetta TDI depreciated 7.9%, while the gasoline Jetta fell 3.5% in value. Lastly, the Beetle TDI fell 6.5% and the gasoline Beetle fell 2.3%.

"It is still very early in the process for Volkswagen, as well as the outcome this may have on overall vehicle depreciation patterns, but we will remain focused on observing these vehicles in the coming weeks at auctions around the country," said Anil Goyal, Black Book's vice president of automotive valuation and analytics.

Black Book aggregates vehicle auction sales data for commercial fleet users.