International ETFs Underweight in 401(k)s as US Tops 60%

U.S. dominance in global equities has become a defining feature of retirement portfolios: by market capitalization the U.S. accounted for approximately 60% of the MSCI All Country World Index as of December 31, 2025 (MSCI). That concentration has coincided with persistent underweighting of international ETFs in defined-contribution plans; industry surveys from Vanguard and BlackRock in 2024–2025 show typical target-date and 401(k) glidepaths holding less than 20% in ex‑U.S. equities. The result is a structural tilt toward domestic performance drivers — technology, high market-cap concentration and dollar strength — which can materially change risk/return outcomes over long horizons. Institutional investors and plan sponsors face a tactical question: whether to rebalance into broader global exposures while valuations and sector compositions diverge across regions.

Context

Retirement portfolios historically used international equities as a diversification anchor. Over the decade to 2025, U.S. large caps outperformed many developed ex‑U.S. benchmarks, a gap that widened after 2016 and accelerated in the 2020–2024 recovery period (MSCI, S&P). This relative outperformance has reshaped investor behaviour: net flows into U.S.-focused equity ETFs far outpaced those into international funds in recent years, reinforcing home‑bias. As a result, many defined-contribution plans now show concentrated allocations to domestic equities well above market-cap weights, reducing exposure to secular growth opportunities in Europe, Japan and parts of Asia and to cyclical upside in commodity-linked economies.

The market-cap dominance of U.S. stocks is not new, but the degree matters. With roughly 60% weighting, a portfolio mirroring global market-cap would hold around 40% outside the U.S. By contrast, a number of large retirement plans and popular target-date vintages hold substantially less than that: industry data from 2024–2025 indicates median ex‑U.S. allocations in some default funds at or under 20% (Vanguard/BlackRock pension studies). The implication for long-term savers is structural exposure to a narrower set of macro and corporate risks — an issue that rarely shows up in short-term performance comparisons but compounds over multi-decade horizons.

For institutional allocators, the question is not binary. International ETFs vary by region, factor exposures, and cost. Broad products such as the Vanguard FTSE Developed Markets ETF (ticker VEA) — expense ratios as low as 0.05% according to Vanguard fact sheets (Feb 2026) — sit alongside regional and factor-specific ETFs that offer more targeted access. The trade-off is between cheap, diversified beta and the potential for higher tracking error or concentrated risk in niche exposures.

Data Deep Dive

Market structure: MSCI’s country weights are the benchmark for many institutional strategies. As of Dec 31, 2025, MSCI reported the U.S. at approximately 60% of ACWI by market cap, with the Euro area, Japan and China comprising the largest non‑U.S. blocks (MSCI, Dec 2025). Currency dynamics magnify these weights in dollar‑denominated portfolios: a stronger dollar can suppress USD returns of foreign equities even when local markets appreciate. From a flows perspective, Morningstar and Bloomberg ETF flow tallies for 2025 showed a pronounced tilt: U.S. equity ETFs accounted for the majority of net inflows while many international funds experienced either modest inflows or outflows, reinforcing allocation gaps.

Cost and liquidity: low-cost developed-market ETFs have become more accessible. VEA’s expense ratio of 0.05% (Vanguard, Feb 2026) and similar pricing from other providers have removed a traditional barrier to international allocation: cost. Liquidity profiles for the largest international ETFs remain robust; for example, top international ETFs typically show average daily volumes in the hundreds of millions of dollars and assets under management in the tens to low hundreds of billions (Bloomberg ETF data, March 2026). The combination of low fees and sufficient liquidity makes rebalancing into international ETFs operationally straightforward for plan sponsors and institutional investors.

Performance comparison: over rolling multi‑year windows the performance gap between U.S. and ex‑U.S. equities has been material. Between 2016 and 2025, U.S. large-cap indices outperformed many developed ex‑U.S. benchmarks on an annualized basis — a pattern driven by sector concentration in mega-cap technology and greater index tilts to companies with stronger earnings growth. However, performance is cyclical: there are historical episodes when developed ex‑U.S. and emerging markets outperformed by double-digit percentage points over multi‑year stretches (MSCI, 1998–2025). The past decade’s U.S. premium therefore increases the potential for mean reversion, especially if valuation spreads compress or if macro leadership rotates outside the U.S.

Sector Implications

Equity sector composition differs materially between U.S. and non‑U.S. indexes. Technology represents a higher share of U.S. indices, while financials, industrials and cyclical commodities are relatively larger in many developed ex‑U.S. benchmarks. For retirement portfolios, these structural sector differences translate into distinct sensitivities: domestic-heavy portfolios are more exposed to growth and multiples expansion, while international exposures can provide offsetting exposure to value-oriented cyclicals and dividend yields.

Geopolitical and macro catalysts differ by region. European equities remain sensitive to domestic fiscal and energy transitions, Japan to policy shifts and corporate governance reforms, and Asia to trade patterns and local monetary cycles. Institutional investors should view international ETFs as tools to access these differentiated drivers rather than as a single homogenous asset class. Tactical allocations can be implemented through broad ex‑U.S. ETFs or through regional/factor ETFs depending on conviction, liquidity needs and governance constraints for plan managers.

For fixed-income-sensitive portfolios, international equities also interact with currency hedging decisions. Hedged international equity ETFs have become more common, enabling plan sponsors to isolate equity performance from FX volatility. The choice between hedged and unhedged international ETFs should reflect long-term liability profiles and currency risk tolerances: hedging reduces volatility from exchange-rate moves but can add cost and complexity.

Risk Assessment

Underweighting international equities introduces concentration risk. A retirement portfolio that deviates materially from market-cap weights concentrates exposure to a narrower set of macro, policy and corporate outcomes. While this bias has benefitted many savers during the U.S. run of outperformance, it creates path dependency: a future period of non‑U.S. leadership could produce prolonged underperformance relative to a market-cap diversified approach. Institutional fiduciaries should document the rationale for any sustained deviation from global weights and stress-test outcomes under multiple regime scenarios.

Operational risks are manageable but non‑trivial. Rebalancing into international ETFs entails attention to trading windows, expense budgets, and potential tax implications for plan participants. Liquidity is generally sufficient for the largest ETFs, but sponsors must avoid slippage by using execution best practices and monitoring bid-ask spreads — a particular concern for narrower regional exposures or for smaller plan platforms. Additionally, currency and sovereign risk in emerging markets can introduce episodic drawdowns that require long-term horizon discipline.

Regulatory and governance risk is rising in some jurisdictions, which can affect index inclusion rules and cross-border listings. Passive international ETFs are subject to index methodology changes that can alter sector or country exposures; sponsors should incorporate periodic reviews into governance frameworks and consider overlay strategies where appropriate to manage timing risk.

Outlook

Valuation spreads are central to the case for revisiting international exposure. As of late Q1 2026, price-to-earnings and price-to-book differentials between U.S. large caps and developed ex‑U.S. benchmarks remain elevated relative to 10‑year averages (FactSet/MSCI, March 2026). If economic leadership normalizes or if currency cycles reprice, non‑U.S. equities could outperform on a multi‑year basis. For plan sponsors and institutional allocators a phased approach to increasing ex‑U.S. weights — through systematic rebalancing or dollar-cost averaging into low-cost international ETFs — can smooth transition risk while restoring market-cap neutrality over time.

Tactical considerations should be balanced with strategic objectives. For investors with long horizons and liability-sensitive objectives, alignment with global market-cap weights reduces single-country concentration and introduces exposure to alternative growth drivers. For those with shorter horizons or specific liability constraints, targeted international allocations — region-specific or factor-tilted — may be more appropriate but require active oversight and justification within plan documentation.

Implementation paths vary: broad betas such as large-cap developed ex‑U.S. ETFs, regional ETFs, and hedged variants all have roles depending on trustee mandates and participant demographics. To support decision-making, plan committees should integrate data on relative valuations, flows, liquidity, and fee economics; for foundational research on ETF allocation and governance, see our institutional resources on ETF Allocation and International Equities.

Fazen Capital Perspective

Contrary to the prevailing momentum narrative that rewarded U.S. centric allocations for a decade, Fazen Capital views the current structure as a narrowing of optionality for long-duration investors. The concentration of market-cap in U.S. mega-caps is not a permanent structural advantage but a cyclical outcome magnified by monetary policy, technology leadership and dollar dynamics. From a portfolio-construction standpoint, restoring a closer-to-market-cap international allocation is a pragmatic way to hedge a regime change that would disadvantage domestic-heavy portfolios.

We also emphasize implementation nuance: low-cost, broad international ETFs remove many historical frictions — fees and tradability — but do not eliminate macro and currency risk. A layered approach that combines broad ex‑U.S. ETFs for baseline diversification with selective active or factor exposures for tactical tilt can preserve liquidity and governance simplicity while capturing region-specific opportunities. Institutional sponsors should set clear rebalancing rules that avoid ad-hoc shifts driven by short-term relative performance.

Finally, the contrarian element is timing. Many investors shy away from international ETFs after a period of underperformance; that behavior amplifies valuation dislocations. For long-horizon retirement portfolios, a disciplined reintroduction of international exposure during drawdowns or through dollar-cost averaging can capture mean reversion potential without relying on market timing. For further discussion on rebalancing frameworks and ETF implementation, see our institutional guidelines at ETF Allocation.

FAQ

Q: How much ex‑U.S. exposure should a typical retirement portfolio hold? A: There is no one-size-fits-all answer; market-cap weight implies roughly 40% ex‑U.S. based on MSCI ACWI as of Dec 31, 2025 (MSCI). Many target-date and 401(k) default funds hold significantly less — often under 20% — which increases domestic concentration. Sponsors should calibrate ex‑U.S. weights against liability profiles, participant demographics and governance capacity rather than benchmarking to peer averages alone.

Q: Are currency-hedged international ETFs preferable for retirement plans? A: Currency-hedged ETFs remove FX volatility but add cost and can reduce long-term diversification benefits if the domestic currency mean-reverts. Hedged products are useful for liability-matched strategies or for sponsors with explicit currency constraints; unhedged exposures remain appropriate for many long-horizon equity allocations. Historical evidence shows hedging reduces short-term volatility but the decision should align with plan objectives and cost tolerance.

Bottom Line

With U.S. equities at roughly 60% of global market-cap (MSCI, Dec 31, 2025) and many retirement plans holding <20% ex‑U.S., there is a measurable diversification gap that low-cost international ETFs can address. Plan sponsors should reassess allocations, document rationale, and consider phased rebalancing to manage transition risk.

Disclaimer: This article is for informational purposes only and does not constitute investment advice.