Customers view Harley-Davidson Inc. motorcycles at the company's dealership in South San Francisco, California, U.S., on Tuesday, June 26, 2018.

Prices for used Harley-Davidson bikes are near historic lows, Chief Financial Officer John Olin said Tuesday.

Used bike sales are actually hurting sales of new bikes, Olin said on a conference call after releasing the company's third-quarter earnings. A drop in U.S. retail sales pushed shares of the legendary U.S. motorcycle manufacturer down by as much as 6.7 percent in morning trading to a 52-week low of $36.15 a share, despite the fact that the company beat Wall Street's profit and revenue expectations.

Although used bike prices are rising, Olin said the cost to buy a used Harley is close to an all-time low when compared with purchasing a new bike.

Auction prices for used Harleys were up in the third quarter over the previous year, and the company said pricing services continue to list higher prices for the company's products. Harley's own dealer network saw rising used-bike prices for the fifth-consecutive quarter.

So relatively cheap "hogs" may not be around for much longer. Despite the fact that low used prices are taking a bite out of new sales.

"We believe used sales are a strong indicator of our healthy brand fundamentals and provide prospects for future new bike sales," Olin said.

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