This note shows that a monopolist facing any linear demand system for n goods and no fixed costs will produce positive quantities of all goods as long as demand is positive for all goods when all are sold at marginal cost. This is in contrast with the traditional view that, in general, a multiproduct monopolist does not produce positive quantities of all goods even though there is positive demand for each of them when prices are equal to marginal cost.

Key words: monopoly, linear demand
JEL Classification: L1, D4

* I thank Rick Flyer, Charlie Himmelberg, Sherwin Rosen, and Larry White for comments on an earlier draft.

** Stern School of Business, New York, NY 10012, tel. (212) 998-0864, fax (212) 995-4218, e-mail: neconomi@stern.nyu.edu, www: http://www.stern.nyu.edu/networks/

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