We've had two of the big bellwether banks report so far, and the results have been mixed.

Citigroup delivered an upside earnings surprise, reporting second quartering earnings of $1.09 a share, which trounced expectations by 12 cents. That led to a flurry of excitement, but as people digested the news, they bid the stock down for the day. It's hard to get too excited about the $2 billion reversal of the credit card loan loss reserves and other bits of good news in light of the 7 percent decline in revenue. Meanwhile, at JPMorgan Chase, revenue rose 7 percent, and that trumps a lot of estimations. It recorded a $1 billion reversal of credit card loan loss reserves.

It's hard to generalize from these two reports as other banks report. It would not be shocking to see other commercial banks also record loan loss reserve reversals. That will help banks offset weakness in trading, where both Citigroup and JPMorgan suffered. We would expect as much at other investment banks, like Goldman Sachs and Morgan Stanley. It just might come down to investment banking.

The deal environment has been strong but it will generate uneven results across the banks. So we should probably stick with our earlier assertion that we'll see more upside surprises. But whether these surprises are cause for celebration or additional worry remains to be seen. Goldman Sachs, Bank of America and Wells Fargo will each report on Tuesday. Morgan Stanley will follow suit later in the week.

For more:
- Breakingviews suggests JPMorgan may be the exception

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