For banks, September to remember in trading

Adam Jeffery | CNBC

What is historically the worst month for the stock market may turn out to be the third quarter's best month for traders, and that could be good news for the nation's big banks.

"September makes it or breaks it," analyst Jeff Harte of Sandler O'Neill said, referring to the month's impact on the third-quarter trading results for the likes of Goldman Sachs and Citigroup.

So far, there have been several encouraging signs suggesting September's activity across different product lines has been stronger than expected. After the typical August lull, and following what some industry watchers describe as a moderate July, September could provide a positive catalyst for the banks' third-quarter trading results.

"Oil, rates and foreign exchange picked up in September from August," said Barclays analyst Jason Goldberg, who also noted debt and equity issuance has been pretty good, and that should have a positive impact on trading.

Still, questions remain about whether it will be enough to offset a very slow August.