The gain was largely driven by the closure of several record-breaking funds: 2017 marked the closure of the largest-ever buyout fund and the largest-ever infrastructure fund, as well as funds ranked among the five largest ever for venture capital, secondaries, growth and natural resources, according to Preqin, a research group tracking such investments.

The organization said that overall, the average size of private capital funds closed in 2017 was $570 million, significantly above the average of $445 million seen in 2016 and surpassing the previous record of $475 million in 2008.

Against a background of low yields from listed equities and many government and corporate bonds, high net worth and ultra-HNW investors have, as previously reported by this publication, pushed into private investment markets, whether they be in private equity, private debt, private real estate and infrastructure. Clients are said to be willing to trade less liquidity for the superior yields available, although there may be signs that a build-up of un-invested spare capital – “dry powder” – could become an issue.

“The record amounts of capital being committed to the industry will be an encouraging sign for fund managers, but there may be concerns about the twin pressures of fundraising competition and capital concentration in the months ahead,” Preqin said.

“Although Preqin expects fundraising figures to rise by up to 10 per cent as more information becomes available, the number of funds closed marks a decline from 2016. While huge amounts of capital are being allocated by investors, fewer funds are reaching a final close than in previous years, with the most experienced and high-profile managers accounting for rising proportions of total fundraising year on year,” the organisation said.

“At the same time, the rate of new funds coming to market is accelerating, and has consistently hit new heights throughout 2017,” it continued.

Preqin noted that at the start of January this year, there are 3,484 private capital funds seeking investment, 2.5 times the number of funds that closed in the preceding 12 months. This figure, it said, is twice the proportion that it was five years ago, a sign of how the fundraising market has become more competitive in recent years. The fund-raising climate could become more “challenging” in future, Preqin added.