By Amey Stone
It has been a bruising spring for Sandy Weill, chief executive of financial giant Citigroup (C) and one of Wall Street's most enduring figures. To avoid any potential conflict of interest in the future, securities regulators restricted the conditions under which he can speak with analysts at his own company. Book publishers failed to pay millions for his memoirs. And his nomination to the board of the New York Stock Exchange incited ridicule. He quickly withdrew from the process.