Internet brokerage Boom Securities yesterday joined the chorus undermining the minimum commission system by announcing a special offer. The firm advertised that a promotional event would be held today and those who registered as new clients would be offered a waiver of commission charges on their trading until August 31. This follows a similar move by Taiwan-based brokerage KGI Asia in which clients registering before the end of next month could trade stock without any commission or handling charges until the end of the year. Boom Securities managing director Mark Duff declined to give details on how the firm would circumvent the 0.25 per cent minimum commission rule. 'That's something we manage internally,' Mr Duff said. On Wednesday, the board of Hong Kong Exchanges and Clearing approved the abolition of the rule with effect from April 1, 2002. An exchange source said the exchange would give tacit consent to such circumventions of the rule in the interim as they reflected the needs of the market.