WMC Mortgage was sued by the securities administrator for a mortgage trust, which accused the subprime loan originator of breach of contract that caused more than $550 million in damages.

The trust was formed as part of a $1.9 billion residential mortgage securitization sponsored by JPMorgan Mortgage Acquisition Corp. and serviced by JPMorgan Chase (JPM), according to the suit, filed yesterday in New York State Supreme Court in Manhattan.