The private equity industry in 2015 continued a recent trend of capital distributions exceeding the amount of capital called up, alternatives data provider Preqin reported Friday.

Last year, fund managers returned a record $443 billion to their investors, up from $424 billion distributed in 2014. This was the third consecutive year in which the level of returned capital hit a record high.

Meanwhile, the amount of capital called up by private equity fund managers in 2015 decreased by 15% from $265 billion in 2014 to $226 billion.

Preqin said the lower levels of capital called up from investors had pushed the total level of capital waiting to be deployed by fund managers to record highs.

As of the end of 2015, the industry held a total of $2.4 trillion in assets, of which $1.7 trillion was the unrealized value of investments still held by fund managers, and $757 billion was dry powder.

By the end of the third quarter, however, the industry’s total dry powder had shot up to $839 billion from $818 billion in the previous quarter. Buyout dry powder represented 63% of available capital in the industry, and had increased by 14% since December, according to the report.

With so much capital available to fund managers, Preqin said, valuations are becoming an increasing concern for the industry. As a result, some institutional investors have downgraded the projected performance of their private equity commitments.

“With the industry returning so much capital to its investors, it is unsurprising that investor satisfaction and confidence in the asset class remains high, with many investors stating in June that they planned to make further commitments before the end of 2016, and target allocations trending upwards across the industry,” Preqin’s head of private equity products Christopher Elvin said in a statement.

Elvin said the massive buildup of capital waiting to be deployed by fund managers, coupled with high asset pricing, are being seen in the difficulty many managers are reporting in finding attractive investment opportunities.

“Ultimately, it may be that these factors result in the net capital flow to investors in the coming year being lower than has been seen in recent years,” he said

Other Key Facts

Last year, buyout funds recorded an average IRR of 17.1%, well above any other private equity fund type, Preqin reported. In the three years to the end of 2015, both buyout and venture capital funds recorded average IRRs above 18%, while over longer periods mezzanine funds offered the greatest rate of return.

The gap between top and bottom quartile private equity funds has been widening among recent vintage funds. Median net IRRs have been rising. Vintage year 2012 funds have the highest IRR, 15.1%, followed closely by vintage 2010 funds, 14.4%, and 2011 funds, 14%.

However, since vintage year 2009, top quartile funds have all recorded IRRs of more than 20%, while bottom quartile ones have not exceeded 10%.

Preqin said that given the continued increase in dry powder available to fund managers and the effect of rising asset pricing, the average size of private equity buyout-backed deals has increased in recent quarters. In the third quarter, the average deal was $405 million, up from $372 million in the April-to-June quarter.

Despite this, the overall level of capital deployed by buyout funds is comparable between the two quarters.