The rule was to come into effect by August 31 but its enforcement was postponed by another month and brokers were given time till September 30. The provision means brokers are obliged to revoke the pledge by October 1. Sources said Sebi had taken a firm stand that lenders who gave loans against shares had taken cognizance of the circular and, in the light of that, verified all collateral. Karvy allegedly raised over Rs 600 crore by illegally pledging securities belonging to 95,000 of its clients worth more than Rs 2,300 crore. Karvy used the securities to generate funds for group entities, including its real estate subsidiary.