russia’s central bank said thursday that it ordered brokers to stop allowing traders to place bets against russian shares a practice known as shortselling short sellers borrow stocks they believe are overvalued and immediately sell them hoping to repurchase the shares for a lower price when they need to be returned and to pocket the difference the moex russia’s benchmark stock index crashed 45 thursday officials earlier had suspended trading on moscow’s exchange before reopening it at 10 am local time