Wealthy people who have at least $100 million will see their fortunes grow the fastest over the next five years as stock markets around the world recover, according to the Boston Consulting Group.

The ultra-high-net-worth investors will be rewarded with compound annual growth rates of about 9.5 percent through 2020 as individual and family fortunes surge to $224 trillion, the consulting firm said in a report Tuesday. The share of global wealth controlled by millionaires will increase to 52 percent from 47 percent in 2015.

Faced with shrinking investment-banking fees, lenders such as UBS Group AG, Credit Suisse Group AG and JPMorgan Chase & Co. are targeting the super rich, offering advice on their companies and their private affairs, including offering personal credit lines of hundreds of millions of dollars.

Wealth management “generates very healthy pretax profit margins and is relatively capital-light, in comparison with other types of banking and asset management businesses,” Daniel Kessler, a partner at BCG in Zurich who co-authored the report, said in an interview.

The growth of worldwide private-household wealth slowed to 5.2 percent in 2015, down from more than 7 percent a year earlier, because of poorly-performing equity and bond markets, according to BCG. The Boston-based firm expects a rebound, with household assets set to advance 5.9 percent annually in the next five years.

Offshore financial centers, where private banks manage money for non-residents, grew assets by about 3 percent to almost $10 trillion in 2015, BCG said. While some investors in North America and Europe have repatriated money to pay taxes, wealthy individuals will continue to use havens to escape economic and political strife at home, or to access financial products not available onshore, according to the report.

“On the offshore side, the business has become much more complex in recent years and we see many players thinking through more carefully whether they want to be in that business,” Kessler said.

Offshore wealth booked in Hong Kong and Singapore is projected to grow by 10 percent annually, with the Asian hubs gaining ground on Switzerland, the largest cross-border booking center with $2.3 trillion.