In a quarterly report published Monday, the BIS reported financial institutions such as pension funds, insurers and shadow banks outside the U.S. have $65 trillion in U.S. dollar debt through foreign-exchange swaps, forwards and currency swaps that aren’t recorded on balance sheets—representing “a large and growing volume of missing U.S. dollar debt.”

The growing load of hidden leverage has swelled to a massive $65 trillion in a largely obscure corner of the foreign exchange market, economists at the Bank for International Settlements warned Monday—making it more difficult to levy the risks lying in the financial sector as experts worry about possible triggers for another global financial meltdown.