"Irene will cost insurers an estimated $2.6B in the U.S. rather than the maximum of $14B projected, as the storm weakened as it hit the East Coast, Kinetic Analysis says. The total economic loss will be smaller too, says Moody’s Mark Zandi. “We’re talking billions of dollars… not tens of billions."

U.S. Economy Currents - Seeking Alpha

In the market, it’s not whether a datapoint is good or bad that is important, it’s whether it’s better or worse than expected. Irene hit the east coast, ripped down power lines, and caused a decent amount of damage. However, it was much less than expected, and that’s why you’re seeing insurers and reinsurers rally today.

Insurers Index ETF