Wells Fargo

Regulators, investors, and policymakers are breathing a sigh of relief about the banks. Profits are up. Bank share prices are surging. And on June 9 Uncle Sam gave 10 banks the go-ahead to pay back $70 billion in bailout funds. "These are early signs of repair and improvement," Treasury Secretary Timothy F. Geithner said in a press briefing.

That didn't take long. The economy hasn't yet recovered from the implosion of risky investments that led to the worst recession in decades—and already some of the world's biggest banks are peddling a new generation of dicey products to corporations, consumers, and investors.

At first glance, banks seem to be recovering nicely from the financial crisis. But investors cheered by optimistic earnings reports could soon face a painful surprise.