Private Markets Shift Puts Premium On Reliable, Transparent Data – ARC

Tom Burroughes

18 December 2025

A dominant theme for wealth managers in 2025 has been the spread of private market investment to affluent investors, breaking it out of traditional redoubts of the ultra-rich and large institutions. That brings with it a need for transparent data that’s also easy to grasp.

Unless a wider audience has credible and understandable data, a drive to encourage a wider take-up of investments such as private equity, venture capital and other non-listed areas will stutter. For policymakers saying they want to boost European growth, this is not just a technical matter.

, to give the full name – is synonymous with the business of collecting and then reporting performance data from contributing firms, doing so for different categories of risk. This work has made it a familiar name in the private client wealth management business over the past 21 years, giving a sense of how these advisors to the wealthy actually perform.

Recent times have kept ARC busy: In July 2025, S&P Dow Jones Indices, part of New York-listed S&P Global, bought wealth data and indices of ARC Research. S&P Dow Jones Indices have the right to use the ARC brand. The agreement didn’t affect ARC’s advisory business, however. (The financial amount wasn’t disclosed.)

Because of the work ARC does with wealthy families, the organisation likes to call itself the “largest multi-family office no one has heard of” – a term that Stephen McMahon (main picture), ARC’s chief executive, likes. At ARC since 2008, and with a background at PwC and the Bank of England, he relishes the new direction ARC is taking.

And part of that direction is grappling with the continued fast rise of private market investing. With Europe’s ELTIF structure, the UK’s Long Term Asset Fund model, and moves by other countries, such as the US, to widen access, it puts ARC in an interesting place.

“We believe there’s a job to be done which is to try and peel back some of the opacity and complexity and give private clients a better sense of how to think about both their private and public portfolios,” he told WealthBriefing in an interview at ARC’s offices in Fetter Lane, on the edge of the City district of London. “We need to work with the private asset managers to push back against the suggestion that people are marking their own homework,” he said, referring to how firms put out their performance figures.

“We are already doing this job for our existing clients, but as private assets become more commonplace, we expect this to become an ever larger part of our business," McMahon said.

McMahon believes that ARC is “very well placed” to generate consistent figures for the private markets solutions, while also taking into account client-specific factors such as speed of commitment and resulting cashflows.

McMahon and colleagues have a major opportunity. The value of global private assets funds has surged to a record $14.05 trillion this year, surging 77 per cent since 2020, and up 205 per cent since 2015. The total is expected to hit $23.9 trillion by the end of the decade, according to Ocorian, the asset servicing firm. Firms, on average, according to UK private bank Brown Shipley, take about 12 years to go to IPO and many don’t bother with that route. The supply of private market opportunities has risen, relative to listed ones, since the late 1990s.

McMahon knows that ARC cannot stand still in this environment. Several organisations have sought to tap demand for data from the private markets space – typically more challenging than for listed stocks. For example, MSCI launched MSCI Private Capital Indexes in July 2024.

Comparing returns from listed equities, which can be traded in seconds on electronic exchanges, with those from venture capital, where time horizons tend to be measured, carries difficulties. Plenty of caveats are needed when comparing stocks’ returns with the internal rates of return (IRR) measures that go with private assets. That said, some yardsticks are better than none, and the sophistication of the investment world is evolving fast. Firms such as Preqin (now owned by BlackRock) also issue indices for private markets.

ARC’s capabilities are important for its advisory and consulting business, aimed as it is at about 250 global families, reaching from Vancouver to Sydney. The consulting side accounts for about two-thirds of ARC’s revenues, McMahon said.

With ARC, it sits on “the same side of the table” as a client, he said, when it comes to clients’ discussions with banks and other financial firms. The confidence that comes from high-quality data also helps foster confidence within families.

McMahon enjoys the varied ways he and colleagues talk to ARC’s clients. “Data is cold – humans are not,” he said. Approaches can range from a formal, sit-down meeting in an office to a less structured one over a video call.”

“A big part of what we do is try to ensure that people remain engaged in investment markets,” he added.