Trading on Egypt's troubled stock exchange has been temporarily halted after the EGX100 index fell 5 per cent in its opening hour. The Bourse froze trade about 11:20am. The benchmark EGX30 index fell 2.91 per cent and the broader EGX70, 6.2 per cent. Under stock exchange regulations placed by the Egyptian Financial Supervisory Authority (EFSA) before Bourse trading resumed in March, a fall of 5 per cent or more for one of the market's indexes results in a 30 minute halt in trade. The heaviest losses are being felt by lower cap firms, but shares in high-caps like Orascom Construction, Telecom Egypt and the Commercial International Bank have all shed 2.5 per cent or more. "There isn't one single concrete reason to explain the drop," says Walaa Hazem, asset manager at HC Securities. "Political and economic indicators are still negative, there isn't enough buying power in the market."