Amazon.com

(AMZN) - Get Report

was down 10.8% in preopen

Island

trading after

Prudential Securities

downgraded it from hold to sell.

Analyst Mark Rowen said the online retailer has shown weak growth in its book, music and video business. In a research note, Rowen said he believes that in a best-case scenario the stock is worth $62, but he cut his price target to $9 from $20.