THE Shanghai stock exchange temporarily suspended A share trading yesterday morning after heavy sell-offs caused prices to plunge in early trading. Trading in the 101 A-share counters at the five trading halls of the exchange was halted at 10.04 am, but re-started in five minutes. Although the suspension managed to stop further dives, the Credit Lyonnais A share index fell 716.81 points or 14.66 per cent to close the day at 4,171.25. Analysts attributed the decline to more stringent regulations on bonus share issues, and to the news that 1.2 billion to 1.5 billion shares were scheduled for listing in Shanghai in the first quarter of next year. Both were announced on Friday after the market close. Also to blame, analysts said, were rumours that China planned to slap capital gains tax of as much as 20 per cent on revenue from investment in stocks. ''It is not often we would make a suspension in this way. But there was across-the-board panic selling, and the computer had become overloaded,'' said an official at the exchange's trading department. Brokers said Shanghai Securities Exchange president Wei Wenyuan had been to the trading hall in the morning, calling on traders to be calm. The Credit Lyonnais Shanghai B share index fell only 19.43 points to close at 976.92. A Shanghai International Securities dealer said: ''The drop was largely triggered by the release of new guidelines on the issue of bonus shares. ''Domestic Chinese investors welcome bonus share issues, as they will give them a chance to be allocated more shares. and at a discount to market prices,'' he said.