So should we believe in the recent rally in bank stocks? Today's Journal hits on one reason to be skeptical:

At the 15 stress-tested banks that have raised capital by selling stock to the public, no senior executives have recently reported buying shares themselves, according to Jonathan Moreland, director of research at The New York firm tracks stock-buying and selling patterns among corporate executives.

In January and February, for example, Bank of America Chief Executive Kenneth Lewis and J.P. Morgan Chairman and CEO James Dimon were big buyers of their company's shares. Bank of America shares are up 263% from their March low, while J.P. Morgan has jumped 118%.

"I would have expected to have seen many more insiders continue bullish purchase activity over the past two months," Mr. Moreland said. "The fact that they haven't feeds into my fears that this is just a bear-market rally."

Interestingly, while the CEOs have been sitting on their hands, the Chinese have been lining up to invest in banks all over again:

Buyers in Morgan Stanley's $2.3 billion stock offering Tuesday were led by China Investment Corp., which got 44.7 million shares for $1.2 billion, bringing its overall stake in the Wall Street firm to about 9.9%. It was the Chinese sovereign-wealth fund's first major public investment in a Western bank since the global financial crisis began worsening early last year.

Which, I think, may lead us to a general rule of investing in financial institutions: Buy when the CEOs are piling in to bank stocks, sell when the Chinese are piling in. It would have served you pretty well to this point.

--Noam Scheiber