Barnes & Noble.com (BNBN) plunged 15.6% in midmorning after it said, following Tuesday's close, that it expects to report a loss of $1.05 to $1.08 a share for 2000, worse than the First Call/Thomson Fianancial estimate of a 95 cent loss. The online bookseller said estimates do not include costs in its acquisition of Fatbrain.com. Prudential Securities downgraded the stock to sell from hold and slashed its price target to $1 from $7. Goldman Sachs increased its 2000 loss estimate to $1.05 a share from 94 cents.