Bank of America Tuesday raised its estimate of potential payouts to settle litigation and disclosed it has been queried by regulators over its foreign exchange trading practices. In its annual securities filing for 2013 the US banking giant raised its estimate of outstanding costs it could pay for litigation and regulatory problems to $6.1 billion; the estimate a year earlier was $4.2 billion. Bank of America has faced major government and private lawsuits over its sale of mortgage-backed securities ahead of the financial crisis. Bank of America said it adjusts the estimate once it concludes a payment is "probable". A US judge in New York earlier this month approved an $8.5 billion settlement between the bank and private investors on mortgage backed securities. The bank also disclosed that it has been questioned by regulators in North America, Europe and Asia "regarding conduct and practices in certain (foreign exchange) markets over multiple years." Bank of America said it is cooperating with the inquiries. Several other banks have also been queried in the wide-ranging foreign exchange probe. Other banks, including Deutsche Bank and Citigroup, have also either suspended or fired currency traders in light of the probe.