Aim/returns: Poor Aim

American regulators and stock market executives have fretted lately over the London Stock Exchange’s junior market, Aim. Based on critical comments by Securities and Exchange Commissioner Roel Campos and NYSE Euronext boss John Thain, there certainly seems to be fear that US exchanges are losing valuable business to the lightly-regulated London bourse, which specialises in growing companies. But angst over Aim’s success in attracting new listings - especially of US companies - neglects an import...