Is it just me or do the regulators have no idea? Why not ban short calls, long puts, short futures - or any sort of risk management tool? How about banning all sorts of speculation? That might work... -GB SYDNEY, March 5 - Australia extended its ban on short-selling of financial stocks on Thursday by almost three months, citing weak markets and defying offshore regulators who have concluded that such bans only made matters worse. The Australian Securities and Investments Commission (ASIC) said it would extend its ban until May 31 in a decision that was widely expected given recent attacks on the share prices of local banks, especially investment bank Macquarie Group <MQG.AX>. “ASIC has decided to continue with its cautious approach and keep the ban in place,” the commission said in a statement. “Any possible loss of market efficiency or price discovery as the result of the continuation of the ban is justified given the current market circumstances,” it added. - - - Despite the ban, Australian bank shares have continued to tumble, with critics such as hedge funds arguing that the local regulator was persisting with a ban proven to have failed here and elsewhere. Macquarie, one of Australia’s most adventurous banks with infrastructure investments worldwide, has lost more than half its value since the short-selling ban was introduced. The four major Australian commercial banks—National Australia Bank <NAB.AX>, Commonwealth Bank <CBA.AX>, Westpac <WBC.AX> and ANZ <ANZ.AX> -- have also been sold down heavily. The financial sector sub-index <.AXFJ> has lost 38 percent since the start of October, compared with a 31 percent fall in the benchmark S&P/ASX 200 index <.AXJO>.