Allstate 3Q profit down 55 pct.

DES MOINES, Iowa — Allstate Corp. said its third-quarter net income fell 55 percent after natural disasters cost the insurer $1.08 billion.

Allstate posted net income of $165 million, or 32 cents per share, compared with $367 million, or 68 cents per share a year ago.

The Northbrook-based property and casualty insurer said revenue rose 4.2 percent to $8.24 billion from $7.91 billion a year ago.

The company’s adjusted operating income was $84 million, or 16 cents per share, compared with $452 million, or 83 cents per share a year ago.

Analysts surveyed by FactSet expected 8 cents per share on revenue of $7.99 billion.

Before Monday’s earnings, Allstate disclosed third-quarter pre-tax catastrophe losses of $1.08 billion, up significantly from the $386 million reported in the 2010 third quarter.