Examples of benefits or costs of the current concentration wave are scanty. Yet it is hard to imagine that the merger of a few oil firms today could recreate the same threats to competition that were feared nearly a century ago in the U. S. , when the Standard Oil trust was broken up. The mergers of telecom companies, such as WorldCom, hardly seem to bring higher prices for consumers or a reduction in the pace of technical progress．On the contrary，the price of communications is coming down fast．In cars，too，concentration is increasing--witness Daimler and Chrysler，Renault and Nissan—but it does not appear that consumers are being hurt．