Sun Life Financial Inc. today reported a third-quarter loss, as the insurance giant said it was “significantly impacted by a deterioration in global capital markets.”

Sun Life said the loss for the quarter was of $396 million, or 71¢ share, down from year-ago net income of $577 million, or $1 per share.

The results for the latest quarter included “credit market impacts” of $636 million, including charges on previously disclosed exposure to Lehman Brothers, Washington Mutual and American International Group.

There also were $326 million of charges related to equity market declines.

Excluding the capital market impact, earnings were $566 million, or $1 a share.

“Unprecedented events in the global financial sector characterized the third quarter and significantly impacted our results,” said CEO Donald Stewart, in a release.

“Despite these extraordinary occurrences, Sun Life is well positioned to manage through this challenging economic environment.”

Stewart added that Sun Life intends to maintain its dividend and “capitalize on the intensifying demand from individuals and corporations for reliable protection and investment products.”

Revenue dropped by more than half to $2.56 billion from $5.7 billion a year earlier. Sun Life Canada contributed $1.28 billion, down from $2.5 billion, while its U.S. arm contributed $546 million, down from $2.05 billion.

Return on equity was -10.2% during the quarter, compared with 14.7% for the same time last year.

Assets under management were $388.7 billion at the end of the quarter, down 9.2 percent from $428.1 billion at the same time in 2007.

Sun Life, whose quarterly dividend is 36¢ a share, said it would maintain its present dividend policy and payout level.