A new study from WealthInsight, the London-based wealth-research and data firm (and yes, they are non-partisan), showed that the United States added 1.1 million millionaires between Jan. 1, 2009 and the end of 2011, the latest period measured. There were 5.1 million millionaires in America at the end of 2011, compared with around 4 million at the end of 2008.
That works out to more than 1,000 millionaires a day under the Obama administration. (They defined millionaires as people with total net worth of $1 million or more, excluding primary residence). (Read more: Rich Will Spend More Under Romney: Poll)
"It's true that Obama has been good for millionaires, at least in absolute terms," said Andrew Amoils, analyst at WealthInsight. "He certainly hasn't been bad for millionaires."
Amoils said that quantitative easing and financial bailouts especially helped the finance sector, which accounts for the largest share of millionaires. It also helped that markets recovered in 2009.
The timeframe is worth noting. Measured against the 2007 peak, when 5.27 million Americans had a net worth of at least $1 million, the nation lost 165,360 millionaires. Their combined wealth is down six percent, to $18.8 trillion from a peak of more than $20 trillion in 2007.
We don't know how 2012 will turn out, though if stock markets continue to strengthen, the millionaire count for 2012 is likely to increase. Wealth Insight says the number of millionaires in America will grow to more than six million by 2016, and their combined fortunes will jump 25 percent over the same period. (Read more: Millionaires Give Nine Percent of Income to Charity)
Where did all the millionaires come from between 2008 and 2011?
Mainly from retail, tech and finance — and in both blue and red states.
Of the sectors adding the largest number of people worth $30 million or more, the retail, fashion, and luxury goods sector ranked first. That was followed by energy and utilities, then tech, telecoms and finance. Transportation and construction saw the biggest drops.
The number of people worth $30 million or more grew 26 percent in Connecticut since 2008, 20 percent in Kansas, 12 percent in Michigan, showing that the wealth creation was nationwide.
Do you think Obama has been good for millionaires?
-By CNBC's Robert Frank
Follow Robert Frank on Twitter: @robtfrank