Nearly half of Chinese millionaires plan to move out of the country in the next five years—a flight that could add to worries over the country's economy, as more money moves offshore rather than being invested or spent in China.

According to a study from Barclays and Ledbury Research, which polled more than 2,000 people worth $1.5 million or more from 17 countries, 47 percent of Chinese millionaires plan to emigrate, while another 20 percent said they don't know if they will move.