A new wave of financial alchemy is emerging on Wall Street as banks and insurers seek to make soured securities look better. Regulators are pushing back, saying the transactions don't have enough substance and stand to benefit bankers and ratings firms.

The deals come as Wall Street firms, buoyed by surging markets, are seeking to profit from the unwinding of the complicated securities that helped fuel the credit crisis. Regulators, meanwhile, are struggling to prevent a recurrence of the crisis.

The popular deals are known as "re-remic," which stands for resecuritization of real-estate mortgage investment conduits.

Wall Street Journal