How much responsibility shareholders should bear for corporate wrongdoing is tough to gauge. As owners of a company, shareholders are also often victims of executive misdeeds.

US District Judge Ellen Segal Huvelle is the latest to face this long-standing dilemma as she weighs the Securities and Exchange Commission's proposed $75m settlement with Citigroup over the bank's failure in 2007 to disclose sub-prime mortgage risks. In refusing Monday to approve the settlement, the judge rightly asked why the agency pursued just two Citigroup executives and why shareholders should pay for their alleged missteps.