Citigroup fails US bank stress tests The latest annual round of bank stress tests in America has thrown up a surprise casualty, with Citigroup, the country's third largest, failing along with three other big banks, MetLife, America's largest life insurer, Ally Financial, and SunTrust. 15 of the 19 big banks did however pass, and many have announced boosted dividends and share buy-backs. More about: Banking, Citigroup, USA