The case law supports the proposition that joint ventures are illegal under the Sherman Act only if unresonable restraints of competition are proven to exist. Put differently, joint ventures are of neutral effect under the Sherman Act: Joint subsidiaries do not of themselves infringe the Act, but on the other hand the formation of a joint venture does not save an otherwise unreasonable restraint of competition. An exception to the abovementioned conclusion may be joint ventures between actual competitors, at least as far as horizontal integration is concerned. In this case a per se rule may apply. Finally, the competitive impact of a foreign joint venture may in some cases be such as to validate it under the Sherman Act where its domestic counterparts would have been struck down.