RECORD turnover on the stock market is causing problems because brokers do not have enough time to input data into the trading system, say officials. Stock exchange chairman Charles Lee Yeh-kwong said the more than 73,000 deals yesterday, which generated a record turnover of $10.2 billion, had forced the exchange to allow traders an extra 15 minutes to input information after a trade had been completed. However, he said the exchange was confident the existing broker-to-broker trading system, which was designed to comfortably handle turnover of only $1 billion, could handle any dramatic increase or decline in the index. ''The stock exchange is a very different stock exchange from that in 1987, both in terms of the settlement system and in terms of the trading system,'' Mr Lee said. ''Our trading system and settlement system are functioning very smoothly. We don't anticipate any problems.'' Mr Lee said he did not foresee any circumstances that would cause the exchange to close as it did for four days in October 1987. When the exchange re-opened, the Hang Seng Index plummeted 33 per cent and the futures exchange crashed. Mr Lee said that unlike six years ago, when programme trading played a major role in the crash of markets around the world, there were now safety systems in place where traders would take over from computer systems. Exchange chief executive Paul Chow Man-yui said that despite the heavy turnover, 92 per cent of trades were settled within two days, or T-plus two, and 99 per cent were settled within three days, or T-plus three. Last week, Hong Kong Securities Clearing Co chief executive Richard Heckinger said the settlement and clearing system could handle turnover of $8 billion, but the computer system might have to be upgraded if turnover climbed to $10 billion. Mr Lee said the heavy turnover would not force the exchange to accelerate the introduction of the much-vaunted and much-delayed automatic trading system, which starts operating on November 1. ''I think we have to make sure the system works smoothly,'' he said. ''We cannot afford any breakdown on the system, especially at this time. We have to proceed cautiously.'' Mr Chow said the $99 million system would be able to handle 200,000 deals - nearly triple yesterday's total of 73,792. However, he said all listed stocks would not be integrated into the system until April. Mr Chow said Oriental Press Group, Sino Land Co, Tai Cheung Holdings, Chevalier International and Hong Kong Realty and Trust Co are the first stocks to trade on the state-of-the-art system and of this group, three will be selected to start trading next month. Mr Chow said short-selling would be allowed after the first 20 stock codes, which account for 50 to 60 per cent of total market capitalisation, joined the system. These counters would require market capitalisation of $10 billion and a public float of $5 billion. ''We will take a very cautious approach. We are changing too many things in a month's time,'' Mr Chow said. With five more mainland stocks scheduled to list in Hong Kong over the next few months, Mr Lee said he believed the market would prefer industrial companies because there were few now publicly traded and it would increase the market's attractiveness.