J.P. Morgan Chase & Co. wants to bar internal communications describing trades with Enron Corp. as 'disguised loans' from being introduced at a trial aimed at forcing insurers to cover $965 million in losses on the transactions, according to court papers.

The 11 insurers, who backed the value of gas trades among Enron, J.P. Morgan and an offshore entity, Mahonia Ltd., refused to honor the claim, arguing the bank had used the trades as camouflage for lending Enron money. Enron, once the world's largest energy trader, sought bankruptcy protection in December.

Keeping the internal documents out of court may be crucial to J.P. Morgan's case, some lawyers say. The $965 million in losses would wipe out almost a third of the $3.1 billion in profit before taxes the bank earned in the first nine months of this year.

"This is a silver bullet for the insurance companies, and the effect of this motion is to place a spotlight on this silver bullet," said former federal prosecutor Christopher Bebel, who's now in private practice in Houston.