The hedge fund '$1 billion club' has grown

The number of global investors with $1 billion or more invested in hedge funds has climbed to a total of 227 over the last year, even as a number of high-profile pension funds withdrew from the space.

Over the past 12 months, 51 new investors joined the "$1 billion club" -- or the group of institutional investors that have put at least $1 billion of their cash to work in hedge funds -- new data compiled for CNBC from alternative asset research firm Preqin showed.

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Amy Bensted, head of hedge fund products at Preqin, noted that the hedge fund industry had generated "mediocre performance" over the last year.

"Although perhaps not the sole cause, a handful of high-profile pension funds have publically announced their intention to scale back their hedge fund allocations," she said.

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"Nevertheless, industry assets have seen notable growth and inflows from investors have continued to pour in, driven by a number of large investors allocating at least $1 billion to hedge funds," she added.

Insurance companies -- which made up the largest group of new entrants to the club in when surveyed the previous year -- were beaten out by private-sector pension funds this year, Preqin found. These accounted for 29 percent of the new entries to the $1 billion group between May 2014 and May 2015.

Among the new $1 billion club recruits was Swiss pharmaceutical group Novartis' pension fund, which upped its allocation to hedge funds from 5 percent to 8.2 percent of its total assets.

This comes despite a number of high-profile pension schemes withdrawing all investment from the hedge fund space last year. These include the largest pension fund in the U.S. -- California Public Employees' Retirement System (CalPERS) -- and the 178-billion-euro ($200-billion) pension fund for the Dutch health and welfare sector, PFZW.

Despite these departures, public pension funds still account for the largest proportion – 25 percent -- of the $1 billion club, unchanged from May 2014.

"At least for now, this appears to be the case among the very few, with other investors and public pension funds filling these vacated spaces, such as Employees' Retirement System of Texas and California State Teachers' Retirement System (CalSTRS) allocating more than $1 billion to the asset class," Bensted added.