To increase transparency, the Dodd-Frank reform law requires traders to post high-grade bonds as collateral for most derivative deals executed on a clearinghouse. Bank of New York Mellon figures investors will need $4 trillion in quality collateral to comply. To get around the requirement, bankers have offered to help traders turn risky securities into the bonds they need. Things should be fine as long as the traders don’t go bust. If they do, the banks will be left with the risky bonds.