Global Equity ETFs: When Diversification Hides Concentration

Global equity ETFs or targeted regional ETFs: the question is no longer choosing one over the other, but calibrating the global-ETF weight in a portfolio to preserve returns while regaining control over concentration risk.

Often described as the “easy button” of equity investing, the global equity ETF combines simplicity, apparent diversification, and low fees. Since 2020, equity flows have structured massively around these products, at the heart of equity ETF flows. But the rising weight of US markets and tech megacaps — amplified by the 2023–2025 rally — has reinforced an implicit concentration. The central question becomes: what global-ETF weighting, and what regional complements, balance performance with risk control?

3 Key Takeaways

• Hidden concentration: by end-2025, a typical market-cap-weighted global equity ETF holds ≈60–65% US equities, of which more than 20% sits in a handful of tech and AI megacaps. → Diversification is weaker than it appears.
• Cyclical vs structural: US outperformance since 2010 played out in a low-rate world; with policy rates still around 3–3.5% in 2025 (Fed, ECB), valuation gaps have become more sensitive to earnings surprises.
• Allocation in practice: portfolios documented in allocation research have often shifted from 100% global ETF exposure toward roughly 60–70% global ETFs combined with 30–40% targeted regional ETFs, reintroducing geographic differentiation without adding excessive complexity.

In-Depth Analysis

Mainstream projections treat the global equity ETF as the neutral baseline: investors start there, then potentially overweight a region. This logic rests on the assumption that market capitalization roughly reflects future economic weight. That is a strong assumption, especially after fifteen years in which US equities outperformed other markets by more than 150% cumulatively between 2010 and 2024 (aggregated OECD/IMF data). For context: US equities versus international equities, by the data.

Raw fact: by end-2025, US real GDP accounts for ≈25% of global GDP, but the United States carries more than double that weight in a standard global equity ETF. These structural distortions on the allocation side connect to the blind spots covered in our analysis of the illusory continuity between ETF liquidity and underlying-market liquidity. Europe, developed Asia, and emerging markets are mechanically underweighted relative to their economic weight, while part of 2026–2030 earnings growth is expected to come from those regions. This gap suggests that a global equity ETF is not “neutral” but an implicit bet on continued US dominance and on AI-megacap leadership.

Notable point: part of the consensus expects that as long as the semiconductor war and the US tech premium persist, the global equity ETF remains the best approximation of the global market. The analysis here diverges slightly: the risk is not that this view is wrong, but that it may already be fully priced into current valuations, while potential positive catalysts sit more in Asia, industrial Europe, and selected emerging markets.

Direct Implications for Investors

The relevant question is not “is it time to exit global equity ETFs?” but “how to hold them without passively absorbing US and tech concentration.”

• Allocation framework: for long-term horizons (8–15 years), one structure frequently referenced in allocation research is 60/30/10 — 60% global equity ETFs, 30% regional ETFs (Europe, Asia, emerging markets), 10% cash or bonds depending on the profile. Portfolios built along these lines have combined simplicity with explicit geographic weighting.
• Position sizing: allocations above 80% in a single global equity ETF correspond, in practice, to a concentrated bet on the US cycle and on the persistence of elevated tech multiples — a structural exposure rarely surfaced by passive labelling.
• Adjustment signals: when the US equity valuation premium (12-month forward P/E) exceeds Europe or emerging-market multiples by more than 25–30%, and when ex-US PMIs hold sustainably above 52 for several months, regional ETF exposures have historically gained relative momentum. This dynamic complements the rotation already observed in 2025.
• Risk parameters: conservative portfolios documented in allocation studies typically cap thematic or sector ETFs at 1–2% of capital, with global equity ETFs representing 40–60% of the broader equity sleeve. The remainder has been allocated to less concentrated or equal-weighted vehicles.

Weak Signals to Watch

One parameter still poorly interpreted is the impact of real rates and global liquidity on the geographic hierarchy of equity returns.

• US vs ex-US P/E spread: with US equities trading around 20x forward earnings and Europe at 13–14x, as observed in early 2025 (aggregated Fed/ECB estimates), a narrowing of that spread through ex-US relative outperformance is a credible 3–5 year scenario.
• Monthly flows into global ETFs: a sharp slowdown in inflows (for example, from ≈+$10bn per month to less than +$3bn) combined with acceleration into emerging-market or European ETFs would signal that part of the market is shifting its reading framework.
• US yield curve and credit spreads: a normalization of the curve (less inversion) alongside stable credit spreads would point to more balanced global growth, hence an environment historically more supportive of ex-US markets.
• Implied volatility (VIX) vs European indices: if the VIX stays moderate (15–18) while implied volatility on Europe or emerging markets falls faster, this signals risk perception diffusing beyond the US, a backdrop historically more favorable to geographic arbitrage.

Plausible Medium-Term Scenarios

Current global growth projections for 2026–2027, from major institutions (IMF, OECD), point to 2.5–3% per year, with a slight edge for selected emerging markets. On that basis, three plausible trajectories for global equity ETFs:

Scenario 1 — Continued US Leadership (Consensus Case)

Moderately positive real rates, AI-driven productivity gains, and resilient megacap tech margins. Global equity ETFs continue to outperform a majority of regional ETFs, but with annualized returns somewhat below the 2010–2020 decade (for instance 5–7% nominal versus 8–10%). In this case, allocations of 60–80% to global equity ETFs have remained internally consistent, with a tactical sleeve to capture localized catch-up dynamics.

Scenario 2 — Gradual Ex-US Catch-Up

This scenario rests on European and selected emerging-market earnings growth surprising to the upside, while US multiples compress under the effect of structurally higher rates than the previous decade. Global equity ETFs still perform respectably, but a 50% global / 50% diversified regional mix outperforms. The market does not appear to fully price this possibility today, focused as it is on AI megacaps. Worth reading alongside: how to compare ETFs beyond the label.

Scenario 3 — US or Tech Shock and Concentration Unwind

More aggressive regulation of major platforms, a US credit crisis, or a simple deflation of the tech premium would translate into clear underperformance of global equity ETFs versus more balanced baskets. This is not the central case, but the relative drawdown risk is real, given current concentration.

What could invalidate these three scenarios: additional monetary tightening (for instance, US policy rates moving back toward 4–4.5% in 2026), or a global demand shock, both of which historically hit cyclical markets harder — typically those located outside the US. The market is also watching central banks closely: a major policy error would call the current hierarchy into question.

For investors, the issue is not “guessing” which scenario will prevail, but constructing a portfolio that is not captive to a single one. In practical terms:

• Individual investors: global equity ETFs as a backbone (40–70% of the equity sleeve), complemented by 2–3 regional ETFs and rebalanced annually using a clear rule (for example, returning to target weights when a bloc drifts by ±5%).
• Companies with export exposure: tracking the performance gap between US indices and key revenue-zone indices to inform investor communication and treasury management, in line with broader market-trend analyses.
• Professional or semi-professional managers: a simple KPI such as “US weight in the global ETF / US weight in global GDP” can serve as a quarterly concentration indicator.

Frequent questions on this topic:

• Is a single global equity ETF sufficient for a beginner? For an entry position, a global equity ETF has historically been preferable to a scattered selection of single stocks. Beyond a few thousand euros, gradually adding European or emerging-market ETFs has allowed investors to regain control over concentration risk.
• When has reducing the global-ETF weight in favor of regional ETFs been informative? Three useful signals: a very wide US/ex-US valuation gap, sustainably improving ex-US PMIs, and capital flows redirecting toward Europe or emerging markets. The convergence of these signals has historically made geographic rebalancing more robust.
• Does belief in a US crash justify replacing a global ETF entirely with regional ETFs? A 100% replacement amounts to a strong bet on a specific scenario. For most profiles, reducing the global-ETF share (for example from 70% to 50%) and adding less correlated ETFs has historically offered a more measured risk profile than wholesale switching.
• Are equal-weighted global ETFs a better solution? They reduce megacap concentration but increase the weight of small and mid caps, hence volatility. They have served as a complement more often than as a complete substitute.

Underlying many of these questions is whether it is “too late” to keep loading US exposure via a global equity ETF. The nuanced answer: not necessarily too late, but no longer free in terms of concentration risk. A reasonable balance varies by profile, but the underlying logic is consistent — global equity ETFs as a backbone, regional ETFs to restore relief in the allocation. A related read: the checklist for evaluating an ETF.

We will revisit this with a possibly different market tomorrow.

3 Key Points

• A global equity ETF is not neutral: it concentrates ≈60% on the United States and on AI megacaps, creating implicit concentration risk.
• A 60% global ETF / 40% regional ETF structure has often offered a better balance between simplicity and risk control.
• Tracking the US/ex-US valuation gap and regional ETF flows informs decisions on when to reinforce or trim the global-ETF backbone.

Last updated — 12 July 2026