The International Petroleum Exchange (IPE) in London is understood to be considering a rule change in the light of allegations of price manipulation. The rule would limit the number of settlement trades that could be traded in its Brent Crude oil futures in rollover months to just 500 trades. While the exchange, headed by Dr Richard Ward, refused to comment, members have confirmed that the rule change has been discussed with them. The recent allegations by a former IPE compliance head are that large volumes of day trading, where positions are not held overnight, have 'systematically' impacted the settlement price of IPE's flagship contract. While the rule change would still allow day trading in the cash settled contract, it would severely limit the impact the trades had on IPE's settlement price calculation. In response to the allegations (Financial News, May 28), IPE said it would 'rigorously follow up any suggestions of impropriety' but that it awaited further evidence to support the allegations.