Cash continues to flood into the private capital industry – and to a shrinking number of funds.

Nearly two-thirds of all capital raised during the first three quarters of 2018 went to funds with $1 billion or more, according to Preqin data released Thursday. In total, private capital funds – including private equity, private debt, real estate, infrastructure, and natural resources – have raised $577 billion this year. 

Although fundraising has slowed from last year, when $660 billion was raised in the first three quarters, it is still at a high level compared to recent years: The fundraising totals over the first three quarters of 2016 and 2015 were $548 billion and $520 billion, respectively, according to the Preqin report.

The total number of funds that have completed raising capital in the first three quarters of this year, however, has fallen sharply to 1,197, from 1,670 in the same period of 2017, the report shows. This 28 percent decline in new funds, compared with the nearly 13 percent drop in fundraising, means they're attracting more money on average.

According to Preqin, 11 of the 100 largest ever private capital funds have closed during the first three quarters of 2018 – a number that could climb before the year ends. The data firm pointed to SoftBank’s Vision Fund and the fourth Global Infrastructure Partners fund as examples of “unprecedentedly large funds” that are currently seeking capital.

The trend of capital concentration can be seen across most private asset classes.

In private debt, for instance, second-quarter fundraising was dominated by “several exceptionally large funds,” Tom Carr, Preqin’s head of private debt, said in the report. The five largest funds secured $28 billion – 66 percent of that quarter’s total, he said.

In infrastructure, the number of funds closed during the third quarter dipped to 20, from 27 in the same period last year – even as quarterly fundraising spiked to a new record of $37 billion.  

In natural resources, 17 of the funds closed during the third quarter secured $500 million or more, with seven investment pools raising more than $1 billion.

And in private equity, 55 percent of all capital raised during the third quarter was secured by the 10 largest pools – the biggest being the Carlyle Group’s $18.5 billion buyout fund, which closed at the end of July.

[II Deep Dive: Everything About Private Equity Reeks of Bubble. Party On!]

Capital “is increasingly being concentrated among a small number of large fund managers,” according to Christopher Elvin, Preqin’s head of private equity.

“This is a trend we have noted before, but it is accelerating, possibly in response to investor uncertainty,” Elvin said in the report. “With half of investors expecting public markets to see a downturn within the next 36 months, they may be seeking the security of fund managers with whom they have an existing relationship, and who have a proven track record.”