Stock futures drop on swine flu, banks

U.S. stocks were set for a lower open Tuesday morning as the WHO increased its threat level for the swine flu outbreak and investors were concerned about the implications it could have on the global economy trying hard to recover.

Meanwhile, financial crisis worries also took center stage as Bank of America (BAC) and CItigroup (C) have been told by regulators that "stress test" results show they may need to raise additional capital, The Wall Street Journal reported.

More here: Before the bell: Stocks set to plunge on swine flu, banks