Firms undertake a variety of actions to reduce risk through diversification, including entering diverse lines of business, taking on project partners, and maintaining portfolios of risky projects such as Ramp;D or natural resource exploration. By a well-known argument, securities holders do not...

We examine the pricing implications of call externalities, the benefits enjoyed by the recipient of a message sent by another user. We show that, with or without a network-profitability constraint, efficient pricing requires consideration of demands, as well as costs. We present conditions under...