The European Central Bank (ECB) is running the risk of bankruptcy due to the scale of its exposure to the struggling European economies, a think-tank has claimed.Open Europe has calculated that the ECB's exposure to struggling eurozone economies amounts to €444 billion, of which €190 billion is exposure to the Greek state and Greek banks.Director of the organisation Mats Persson said the ECB's actions may have brought short-term benefits, but they have made the long-term situation worse.He said the transfer of risks from struggling banks and governments on to the ECB could lead to a "potentially huge" bill for taxpayers in order to stop the euro from collapse, as they are the "ultimate guarantor" of these risks."There's a real risk that these assets will face radical write-downs in future with eurozone governments and banks teetering on the edge of bankruptcy," Mr Persson said, highlighting that the zone's taxpayers will have to cover the cost of any failure.The euro continues to gain strength on the foreign exchange market as concerns ease over a possible solution for Greece's debt.For more information on foreign exchange treasury services and risk management, visit our Corporate FX site