NEW YORK – North American stocks posted the best risk-adjusted returns in the past three years as stimulus from the Federal Reserve helped spur profit growth and investors sought a haven in the world’s largest equity market.

The MSCI North America Index of 702 companies has rallied 2 percent since the end of 2009, after taking into account price swings, the most among 19 regional and global equity benchmarks, according to the Bloomberg Riskless Return Ranking.

Volatility in the United States and Canada declined by 38 percent from the previous three years as equities recovered from the worst bear market since the Great Depression.

North American stocks have provided more stable returns as Europe’s debt crisis and inflation concerns in emerging markets prompted investors to seek safety in U.S. corporations.

Fed Chairman Ben Bernanke’s focus on lowering the unemployment rate has helped speed the U.S. recovery, as the central bank took unprecedented measures to stimulate growth before its counterparts in other regions.

“When we fell off the edge in ’09, our policymakers didn’t hesitate in turning on the monetary spigots to full,” said Paul Attwood, who helps oversee $14.7 billion at Huntington Asset Advisors in Cincinnati.

“European counterparts were hesitant to do the same,” he said. “In the emerging markets, they were tightening policy up until about 12 months ago. That’s not an equity-friendly environment.”

The risk-adjusted return, which isn’t annualized, is calculated by dividing total return by volatility, or the degree of daily price variation, and gives a measure of performance per unit of risk. Higher volatility means the price of an asset can swing dramatically in a short period, increasing the potential for unexpected losses.

U.S. stocks make up about 91 percent of the MSCI North America Index.

The MSCI World Index, which tracks stocks across all 24 developed market countries, had the second-biggest risk-adjusted return since the end of 2009, climbing 1.4 percent.

Huntington’s Attwood and Steven Bulko of Lombard Odier Investment Management predict that the risk-adjusted outperformance by North American shares won’t last. Greater room to ease monetary policy will help lift emerging market stocks, Attwood said.