On the recommendation of federal regulators, the...

On the recommendation of federal regulators, the Chicago Board of Trade has increased its margin requirements for investors who speculate in the stock index futures traded on its floor. Other exchanges that offer the financial instruments did not follow the CBOT’s lead. Initial speculative margins were increased from $12,000 to $15,000 per contract. Maintenance and hedge margins were left unchanged at $10,000 a contract, said exchange spokesman William C. Murschel.