Settlements of U.S. class-action securities lawsuits rose 39 percent in 2009, and the amounts could rise further as cases stemming from the financial crisis work their way through the courts.

There were 103 settlements totaling $3.83 billion last year, up from 97 settlements totaling $2.75 billion in 2008, according to a study set for release on Wednesday by Stanford Law School and Cornerstone Research.

Two settlements accounted for 39 percent of last year's total: $925.5 million paid by UnitedHealth Group Inc over the backdating of stock options, and $586 million to end eight years of litigation against hundreds of defendants over initial public offerings.

The median accord was unchanged from 2008, at $8 million.

Joseph Grundfest, director of Stanford Law School's Securities Class Action Clearinghouse, said recoveries tended to be higher when large public pension funds led lawsuits, the U.S. Securities and Exchange Commission pursued related civil charges, or accounting violations were alleged.

Institutional investors were lead plaintiffs on 65 percent of the settlements, the highest percentage since the 1995 federal reform of class-action litigation, including who could serve as lead plaintiffs.

Last year's settlements were well below record $18.3 billion in 2006, including $7.2 billion over Enron Corp.

Other busy years were 2005, when the $10.02 billion of settlements included $6.2 billion related to WorldCom Inc, and 2007, when the $7.36 billion of settlements included $3.2 billion for Tyco International Ltd.

Experts have said settlement totals should rise as cases tied to the 2008 stock market decline and credit crisis are addressed. They said such cases may fare better when plaintiffs show companies intended to defraud or deceive them, not simply that they guessed wrong about the economy or markets.

According to the study, the law firm Coughlin Stoia Geller Rudman & Robbins LLP handled 26 percent of last year's settlements, more than any other firm.

Bernstein Litowitz Berger & Grossmann LLP has the highest median settlement as a percentage of estimated damages, 4.2 percent, among the five law firms with the most settlements.

(Reporting by Jonathan Stempel, editing by Matthew Lewis)