The bank, which has already taken huge write-offs because of its exposure to bankrupt companies like Enron and Global Crossing, is one of the three biggest lenders to Williams Communications Group Inc., which said yesterday it may seek bankruptcy protection. 

Wall Street analysts said Lehman, J.P. Morgan Chase & Co., Merrill Lynch, Bank of America and Citigroup are among the biggest lenders to Williams, which faces an estimated $500 million in interest payments this year. Under bankruptcy, banks would not likely get loans paid back in full, not to mention loss of interest payments. 

The news is particularly bad for J.P. Morgan, since it has already been forced to write off $2.6 billion from the collapse of Enron and $400 million for exposure to Argentina. The bank is also said to have $94 million in exposure to now-bankrupt Global Crossing and $1 billion in exposure to Tyco, which has not filed for bankruptcy but is facing financial difficulties. 

J.P. Morgan has about $90 million of exposure to Williams. Lehman was the biggest lender, with $150 million of exposure. Bank of America has $120 million, and Citigroup and Merrill have about $70 million each, according to a source familiar with Williams' debt situation. 

"By almost any measure of credit quality, J.P. Morgan is on par with its peers or better off," said a spokesman, who declined comment on the bank's exposure to Williams. 

J.P. Morgan is the biggest corporate lender, with a total loan portfolio of more than $105 billion.