Female millionaires tend to favor health and humanitarian causes, according to the study. Millionaires who earned their wealth in finance donate mostly toward academic and cultural causes.
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But when the rich are divided by region, the results vary widely. In developed economies like the U.S. and Europe, health and culture are the top causes for millionaires. In developing economies, education ranks first for giving.
In the Americas, 20 percent of millionaires preferring to give to health causes. Culture ranked second, with 19.7 percent, followed by education and humanitarian causes.
In Asia, education dominates, with 27 percent giving to education, while a much smaller number gave to culture and health care. In Africa and the Middle East, 29.6 percent contributed to academic causes.
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The study also found that millionaires around the world are self-made businesspeople who want to translate their business success into philanthropic results.
"An increasing number of millionaires are focusing on applying business acumen to their chosen cause," said Ouliana Vlasova, head of content at WealthInsight.
—By CNBC's Robert Frank. Follow him on Twitter
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