Morning roundup: More firms "too big to fail"?

Here's a look at this morning's banking and finance headlines:

• Global regulators might expand the definition of "too big to fail," imposing capital rules on more domestic financial firms, Bloomberg reports. Regulators say they expect framework to be in place for "domestically systemically important banks" by the end of the year.
• Reuters explains the "January effect" - a phenomenon where traders sell stock at the end of the year for tax reasons and then begin buying again in January, often favoring small companies - and says it might be a good time to add bargain-priced small caps to your portfolio.
• Rivals are scrutinizing Republican front-runner Mitt Romney's record at Bain Capital - and as a result, the private equity industry has also come under attack, with critics accusing such firms of slashing jobs, the New York Times reports.
• Bank of America has named David Killingback head of mergers advisory for its Asia-Pacific region, part of an overhaul of senior management at the Charlotte company's investment bank in the area, Bloomberg reports.
• U.S. stocks opened lower this morning on concerns of a weakening European economy, the Wall Street Journal writes. Financials and energy stocks led the decline.