The concentration risk hiding in plain sight

When the most transformative companies in the world go public in quick succession, it is easy to get swept up in the excitement.

But for Australian financial advisers, the listing of SpaceX and the anticipated IPOs of OpenAI and Anthropic raise a more pressing concern. Index concentration risk in Australia is growing, and most portfolios have never been built to absorb it.

Daniel Liptak, head of distribution at Melbourne-based Datt Capital, did not mince word about the scale of the shift underway:

“Most Australian advised portfolios have never been stress tested for single name concentration at the index level. What’s coming is not a marginal shift but a structural one, and it’s happening largely on autopilot.”

The mechanics behind the shift

The driver is not simply the market capitalisation of these companies. Sweeping changes to index inclusion methodologies are accelerating their path into benchmarks.

Nasdaq’s revised rules, effective 1 May 2026, allow newly listed companies ranked in the top 40 by market cap to enter the Nasdaq 100 within just 15 trading days. FTSE Russell has shortened its post-IPO seasoning period to five days. S&P Dow Jones Indices is consulting on halving its own seasoning period and waiving the four-quarter profitability test for the largest issuers.

The upshot, according to Apollo’s chief economist, is striking. The top ten S&P 500 constituents could soon account for nearly half the index’s weight, up from around 40 per cent today.

Consider a standard Australian balanced portfolio with 20 to 25 per cent allocated to international equities. Most of that allocation benchmarks to the S&P 500 or Nasdaq 100. That means one to two per cent of total assets sits concentrated in three specific pre-revenue or early-revenue mega-cap technology and aerospace companies.

“This level of concentration is something that most investors would never have consciously chosen,” Liptak says.

Bloomberg Intelligence estimates that S&P 500 index funds alone would need to purchase nearly a fifth of SpaceX’s available float within six months of inclusion. Russell 1000 and Nasdaq 100 trackers face similar pressure.

Triple exposure and the super fund problem

The issue is more complex than it first appears. Many Australian super funds have been actively building private equity and venture capital books. A meaningful portion of that capital flows through global venture managers holding late-stage positions in all three of these companies.

Coatue Management, Dragoneer, Founders Fund, Iconiq and D.E. Shaw all participated in Anthropic’s February 2026 funding round, which valued the company at $380 billion. Those same managers hold LP commitments from major Australian super funds including Hostplus, AustralianSuper and Australian Retirement Trust.

“That exposure already exists and it’s just less visible in client reporting,” Liptak says.

Crucially, private positions do not unwind when companies list. PE and VC funds operate on 10 to 12-year horizons. Pre-IPO exposure sits alongside new public market exposure rather than netting it out.

For some clients, that creates three simultaneous layers: existing private market exposure, existing public market exposure and additional mechanical exposure created by index inclusion.

The Your Future, Your Super performance test compounds the problem. It benchmarks MySuper products against indices, creating a structural incentive for the largest super funds to stay closely aligned with benchmarks, even as those benchmarks become more concentrated.

“The funds aren’t going to be the ones to push back against this,” Liptak says. “The mitigation will need to happen at the individual portfolio level.”

Five steps advisers can take now

Liptak outlines five practical responses to index concentration risk in Australia.

First, measure look-through exposure across all vehicles. Most portfolios have not been constructed with aggregated single-name concentration in mind. Second, update concentration limits on a look-through basis. Third, reassess the passive-active mix in international equities.

“Passive vehicles will automatically absorb whatever weight these companies get in the index. Active managers retain the discretion to underweight or exclude them. That makes the manager structure decision a direct portfolio call, not a neutral implementation detail,” he says.

Fourth, reconsider the case for reducing home bias given the current environment. Fifth, ensure alternative allocations provide genuinely differentiated exposure rather than another form of equity beta.

Liptak points to the Australian small and mid-cap segment as one practical diversification option. The roughly 300 to 400 listed companies outside the ASX 50 carry lower analyst coverage, less index-driven price formation and returns more closely linked to business fundamentals.

The Datt Absolute Return Fund and Datt Small Companies Fund are both benchmark-aware but not benchmark-constrained. That attribute takes on new relevance as passive flows reshape the US large-cap landscape.

“We’re not suggesting Australian small and mid-caps are a substitute for international equities,” he says. “The more relevant point is that, in an environment where international equity exposure is becoming structurally more concentrated through factors beyond investors’ control, the Australian small and mid-cap segment offers one of the few listed equity allocations that can provide a genuine structural offset.”

For advisers navigating index concentration risk in Australia, the message is clear: the window to get ahead of this is now. Waiting for client statements to reflect the shift is already too late.

Start with a look-through exposure audit, revisit your passive-active split and make the manager structure decision a deliberate one rather than a default.