The wealthiest 1 percent now control 39 percent of the world's wealth, and their share is likely to grow in the coming years, according to a new report.

The world's total private wealth grew 7.8 percent last year to $135 trillion, according to the Boston Consulting Group's Global Wealth report. The top 1 percent control $52.8 trillion, and those worth $5 million or more control nearly a quarter of the world's wealth.

(Read More: Surging Stock Market Cheers Up the Rich)

That concentration is likely to increase in the coming years as the wealth of the wealthy grows faster than overall global wealth. The number of millionaires in the world surged by 10 percent year, reaching 13.8 million. The study predicts that global wealth will grow around 4.8 percent a year over the next five years—though millionaires will see their wealth grow nearly twice as fast.