Fears of the US credit crisis are heating up, and the market value of bank stocks has evaporated by more than 100 billion US dollars

Compared with the collapses of First Brands Group and Tricolor Holdings, the losses disclosed by regional lenders Zion and Western Union appear small, amounting to tens of millions of dollars rather than billions of dollars. However, successive revelations of loan fraud have reignited a debate on Wall Street over whether an era of laissez-faire capital is costing banks and non-banks alike. In the cases of Zion and Western Union, the alleged perpetrators were the same: investment funds linked to the likes of Andrew Stupin and Gerald Marcil borrowed money to buy distressed commercial mortgages. The disclosures add to other recent lending explosions, including the bankruptcy filing last month of subprime auto lender Tricolor Holdings, which wiped out almost all of its debt. Then came the collapse of auto parts supplier First Brands Group, which owes more than $10 billion to some of Wall Street's biggest Financial Institution Groups. Stock markets reacted strongly: On Thursday, the 74 largest US banks lost more than $100 billion in market value.