new york (Bloomberg) — Leon Cooperman's Omega Advisors Inc. increased its stake in business insurer XL Capital Ltd. in the third quarter as the Bermuda-based company was racking up a loss of $1.62 billion.

Omega, the hedge-fund manager based in New York, bought 4.53 million more shares of XL Capital, according to a regulatory filing yesterday, and held 4.78 million as of September 30.

Omega's stake amounts to around 1.4 percent of the 330 million shares outstanding.

XL has lost 87 percent since the start of the year as investment losses depleted capital. XL sold more than $2.8 billion in stock in July, partly to rescue the insurance operations of bond guarantor Syncora Holdings Ltd.

Omega bought new positions in UnitedHealth Group Inc., the largest US medical insurer, and Aetna Inc., the third-largest U.S. health insurance company. Omega added 99 million UnitedHealth shares and 29 million Aetna shares. Both companies reported drops in profit last month.

Amid falling oil prices, Omega also lowered its energy holdings by selling its positions in Anadarko Petroleum Corp., Husky Energy Inc., ConocoPhillips and Apache Corp. Crude oil prices have tumbled about 60 percent since reaching a record $147.27 on July 11.

Cooperman founded Omega in late 1991 after 25 years at Goldman Sachs Group Inc.