Who are you going to believe on Amazon.com ( AMZN), Bill Miller or Tom Underwood? Miller -- as anyone who's ever read about how hard it is to consistently beat the market knows -- manages the ( LMVTX) Legg Mason Value Trust , the only fund to top the S&P 500 in each of the past 11 years. His value fund owns 30.2 million Amazon.com shares -- at 6.06% of the fund's assets on Sept. 30, it was the fund's No. 4 holding. Miller and other Legg Mason fund managers are true believers in Amazon.com: Combined, Legg Mason funds own 16.58% of the online retailer, second only to Amazon chief Jeff Bezos. Miller & Co. think the stock, trading at $22, may rise to $30 in the next 12 to 18 months -- and if all goes well, it could climb to $100, Miller has said. On the other side of the Chinese wall at Legg Mason sits Underwood, the e-commerce analyst who last month took over the Amazon beat from Holly Gustafson, who had maintained a buy or strong buy rating on Amazon since November 2000. On Nov. 15 Underwood began his Amazon coverage with a hold rating, saying he would be more comfortable with a valuation in the $12 to $16 range. If the stock is 27% to 45% overvalued, why not a sell? "We cannot think of a catalyst that would cause Amazon's valuation to be materially adversely affected in the next few quarters," Underwood wrote. A bearish call on Amazon is nothing new -- on Friday, Prudential Securities analyst Mark Rowen slapped a $10 target on the stock. Indeed, the stock has soared 100% this year, inviting a slew of Web and retail trackers to deem it too frothy. (Amazon is one of only two stocks with a market capitalization greater than $5 billion to double so far in 2002 -- Gold Fields ( GFI) is the other, according to Baseline.) What makes Underwood's call on Amazon noteworthy is the conflict of perspective on Amazon within Legg Mason. The opposing viewpoints crystallize the debate over whether Amazon continues to deserve the rich valuation the market affords it, and whether Legg Mason will be rewarded or punished for making such a large bet on the highflier.