12 Hottest U.S. Cities for Millionaires

The population of U.S. individuals with investable assets of $1 million or more grew to 4 million in 2013, up 17% from the previous year, according to a report from Capgemini and RBC Wealth Management.

The U.S. Wealth Report 2014, released last week, said investable wealth of high-net-worth individuals increased by 18% to reach $13.9 trillion.

Growth rates of both the high-net-worth population and their wealth in the U.S. exceeded global averages of 15% and 14%, respectively.

For purposes of the report, investable assets excluded primary residence, collectibles, consumables and consumer durables.

The report said continued economic recovery, strong equity market performance, rising real estate values and an "energy renaissance" that pushed U.S. oil production to its highest levels in two decades had boosted the population and wealth of high-net-worth individuals in the U.S. to record levels in 2013.

Twelve cities, generally including important neighboring counties, drove that growth, according to the report. These are home to 69% of wealthy individuals and 75% of high-net-worth wealth.

"Steady GDP growth, reduced unemployment, a falling deficit and an energy renaissance boosted investor confidence and energized risk appetites in 2013," John Taft, chief executive of RBC Wealth Management-U.S., said in a statement.

"These factors contributed to record wealth levels in the U.S. Over the last five years, some of the strongest growth in wealth occurred in the energy- and technology-centric cities."

This indicates that a broader mix of geographies and industries is driving wealth creation in the U.S., Taft said.

Investing Trends

High-net-worth U.S. investors increased risk-taking with their portfolios in 2013. The report found that they invested one-third of their wealth overseas, up from 20% a year earlier.

This trend was driven by individuals younger than 40, who invested 53% of their wealth in foreign markets.

Equity allocations remained the highest globally at 33%, though down from 38% a year earlier. Fixed income and real estate investments both increased by one percentage point to 18% and 14%, respectively.

Alternative investments saw the biggest increase in allocations of all asset classes, up four percentage points to 13%.

Cash and cash equivalents accounted for 23% of investments, up from 21% in 2013.

Following are the top 12 U.S. cities with the largest high-net-worth populations, ranked by rate of growth in their ranks.