The stock exchange is to lose its third senior staff member this year with Paul Phenix, executive director for compliance, leaving for Australia within weeks. 'It is correct that I am going to leave the exchange but I cannot tell when will that happen as there are some procedures that need to be completed,' Mr Phenix said. No decision has been taken on his successor but exchange sources said an announcement could be made today. 'It could be someone from the option division or someone who has experience in derivative products,' a source said. Mr Phenix has worked at the exchange for nine years and is its most experienced staff member. Former chief executive Paul Chow Man-yiu left the exchange in January while Herbert Hui, deputy chief executive and head of the listing division, will leave at the end of this month. Meanwhile, the exchange will today hold its monthly council meeting which will focus on recent proposals to boost retail investors' use of short selling. The exchange is studying whether to allow smaller investors to conduct intra-day short selling without first having to borrow the stock. Securities and Futures Commission executive director David White said the exchange needed to consider carefully the introduction of the intra-day short selling. 'If investors do not borrow stock before they sell short, the risks could be large if the market were volatile,' he said. 'If the market rises sharply in the afternoon, investors may not be able to afford to buy back shares to close the position. If the investors run away, the brokers and the clearing house will suffer the losses. 'In addition, if a stock is suddenly suspended, investors who sell short will not be able to buy back the shares.' He said the commission would like to study this issue after the exchange has assessed it.