The Philadelphia Federal Reserve's February index of business activity, an indicator of business conditions for manufacturers in the region, posted a surprise decline to -12.5, while a positive reading had been expected.

WSJ: Stocks Extend Declines

The index is calculated by subtracting the percentage of firms saying business conditions are bad from those saying they are good.

CNN: Japanese business sentiment ticks up

The index is based on a survey of 5000 households on their confidence in current and future business conditions, current and future employment and future household income.

FORBES: Is The Fed In a Crisis of Trust?