This article examines requirements tying of a competitively supplied g
ood to a monopolized good, It expands the set of market conditions in
which this instrument is known to be profitable, With heterogeneous, p
rivately informed buyers, a firm can profit by trying two goods even w
hen the demands for the goods are price independent-providing the dema
nds are stochastically dependent. We investigate the profitability of
tying as a response to stochastic demand, as well as the effects of ty
ing on prices and the extent of the market served.