The idea that an incumbent supplier may tie two complementary products to fend off potential entrants is popular among practitioners yet is not fully understood in formal economic theory. We make sense of the argument by formally deriving a dynamic version of the old leverage doctrine. It is...

Tying arrangements recently have been a major and contentious issue in many high profile antitrust cases in the US and Europe. Examples include the Microsoft case, the Visa and MasterCard case, and the proposed GE/Honeywell merger to name a few. This paper conducts a selective review of the...