Shares in StanChart have fallen for a fourth day amid reports US prosecutors have re-opened their investigations into whether the lender withheld information into the possible violation of the sanctions regime on Iran. That comes after the lender entered into a deferred prosecution agreement in 2012.The US Department of Justice, the Manhattan District Attorney and the superintendent of New York's Department of Financial Services have all decided to re-open their original investigations into whether the bank withheld information before reaching the settlement, Bloomberg reported.In 2012, StanChart paid a total of $667m to US authorities to settle allegations that it either hid or disguised the identity of Iranian clients behind billions of dollars worth of wire transfers.As of 12:44 shares of the emerging markets-focused bank were down by 2.77p to 961.9p.