Allstate Insurance reported a first quarter profit of $766 million, up by about 46 percent from a year-earlier profit of $524 million.

The increase was due to improvement in operating income and, to a lesser extent, realized capital gains.

Operating income was $710 million for the quarter, compared to $494 million last year. The insurer said the increase in operating income was primarily due to an improved margins on Allstate brand homeowners and other personal lines along with lower catastrophe losses.

The company said it continued to make progress on its strategy to improve homeowners returns while maintaining auto margins. The property/liability combined ratio for the quarter was 92.1, a 2.8 point improvement from the prior year quarter.

Allstate brand homeowners combined ratio was 80.2 for the first quarter 2012 versus 91.4 for the prior year quarter.

The combined ratio for Allstate brand standard auto was 95.2, 0.2 points higher than the prior year, as the impact of approved rate changes essentially offset the change in loss costs.

Total property/liability premiums written increased four percent from the first quarter of 2011 to $6.46 billion. This jump reflected the acquisition of Esurance which experienced favorable results for net premiums written and units as expected. Allstate brand standard auto premiums written declined 1.2 percent from the prior year, a result the company said it expected due to actions taken to improve auto profitability in New York and Florida and homeowners returns. Allstate brand homeowners and other personal lines as well as Encompass contributed to premiums written growth in the quarter.

“Our focus on improving returns while executing a strategy to offer unique products to different customer segments generated strong results in the first quarter,” said Thomas J. Wilson, chairman, president and chief executive officer of The Allstate Corp. “Maintaining margins in auto insurance and continued implementation of our homeowner profit improvement program resulted in solid returns in our property/casualty business.”

Investment results were also good as higher earnings from limited partnerships and proactive management of the portfolio offset the continuing impact of low interest rates. As a result, this quarter book value per share increased 6.6 percent, the dividend was increased by 5 percent to $.22 per share, and $300 million of common stock was repurchased.

In the fourth quarter of last year, Allstate more than doubled its profit, also on lower catastrophe losses and improved homeowners results.