642 QUARTERLY JOURNAL OF ECONOMICS
by any one customer is known to all companies that sell to him. We think that this is an accurate description of procedures on at least some insurance markets. Many insurance policies specify either that they are not in force if there is another policy or that they insure against only the first, say, $1,000 of losses suffered. That is, instead of being a simple bet for or against the occurrence of a particular event, an insurance policy is a commitment on the part of the company to restore at least partially the losses brought about by the occurrence of that event. The person who buys two $1,000 accident insurance policies does not have $2,000 worth of protection. If an accident occurs, all he gets from his second policy is the privilege of watching his companies squabble over the division of the $1,000 payment. There is no point in buying more than one policy.