Here's who controls 88% of hedge funds' cash

Dalio's Bridgewater passes the $100B mark
Dalio's Bridgewater passes the $100B mark

Wall Street's billionaires club is growing: There are 98 new $1 billion hedge funds, according to research from Preqin, and the funds at that size control 88 percent of all the cash.

There are 659 hedge funds operating with $1 billion or more, most of them concentrated in North America, the report said. It's another reminder that for many of Wall Street's top hedge funds, size matters. And some funds, like Ray Dalio's Bridgewater Associates, just keep growing.

"With the number of managers exceeding $1 billion in assets under management increasing, the $1 billion club continues to control a substantial proportion of the hedge fund industry's assets," said Preqin's head of hedge fund products, Amy Bensted.

However, after a year where many top hedge funds underperformed, the top hedge funds' tight grip on the big bucks became a little looser. Their percentage of cash is down, from 92 percent of available capital, to 88 percent this year, the Preqin report said.

Athit Perawongmetha | Reuters

At a time when some U.S. pensions are , the overall size of the hedge fund industry is struggling to maintain its scale and stature. The Preqin report points out that assets under management across the hedge fund industry shrunk slightly, from $3.16 trillion at the end of the first quarter last year, to $3.13 trillion at the end of the first quarter in 2016.

Here's a look at the biggest members of the billionaires' club:

Top 10 Hedge Fund Managers by Total Assets Under Management

Manager Headquarters Assets Under Management
Bridgewater Associates US $146.3B (As of 29 February 2016)
AQR Capital Management US $74.0B (As of 30 September 2015)
Man Group UK $53.1B (As of 31 March 2016)
Och-Ziff Capital Management US $42.0B (As of 1 April 2016)
Standard Life Investments UK $38.4B (As of 31 December 2015)
Winton Capital Management Ltd. UK $34.5B (As of 31 March 2016)
Millennium Management US $33.0B (As of 1 March 2016)
Renaissance Technologies US $32.3B (As of 31 March 2016)
BlackRock Alternative Investors US $31.0B (As of 31 December 2015)
Two Sigma Investments US $31.0B (As of 31 December 2015)

Source: Source: Preqin Hedge Fund Online

— CNBC's Josephine Bila contributed to this report.