Kelley Blue Book, the California-based authority on used-car values, is up for sale, according to published reports.

According to a Financial Times report cited by a New York Times blog yesterday, two unidentified bankers claim to have an inside scoop on the potential sale. One banker says JPMorgan was hired to manage the sale. The other says Kelley Blue Book is valued at between $500 million and $1 billion.

Although the first edition of the Kelley Blue Book was published in 1926, founder Les Kelley had been producing a list of automobile values since 1918.

The Kelley family sold it to Charlie Cook, a family friend, in the1960s. A Kelley family member managed it through 2000, when Paul Johnson was named president. Charlie Cook died in the 1990s.

The Blue Book, initially published for auto dealers, launched a consumer edition in 1993 and its Web site kbb.com in 1995. The Financial Times said a third banker speculated that a recent lack of traffic to the company's Web site and a rise in capital gains taxes may have played a part in the decision to sell the privately held company.

Kelley's top potential bidders, according to the reports, are AutoTrader.com, Kohlberg Kravitz Roberts & Co., eBay and Google.

Kelley Blue Book spokeswoman Robyn Eckard declined to comment, as did JPMorgan.