VTI vs VXUS: The Boglehead Two-Fund Portfolio Explained

The Classic Question: How Much International?

Walk into any Boglehead forum and you'll find a years-long debate about the right VTI/VXUS split. 100% US? 60/40? Market-cap weighted? It's one of the most contested allocation questions in passive investing, and for good reason: the two funds have diverged dramatically over the past 15 years.

Let's break down what each fund actually is, what the data shows, and how to think about the decision.

What Each Fund Holds

VTI (Vanguard Total Stock Market ETF) holds roughly 3,600 to 4,000 US stocks, from Apple and Microsoft all the way down to micro-caps. It tracks the CRSP US Total Market Index and covers essentially 100% of the investable US equity market. Expense ratio: 0.03%. VXUS (Vanguard Total International Stock ETF) holds roughly 8,000 to 9,000 stocks from every other country -- developed markets like Japan, the UK, Germany, and Canada, plus emerging markets like China, India, and Brazil. It tracks the FTSE Global All Cap ex US Index. Expense ratio: 0.07%.

Together, VTI plus VXUS at the right weights gives you the entire global equity market in two funds.

The Performance Gap

This is where honest discussion gets uncomfortable for international advocates. Over the past 15 years, the US market has dramatically outperformed international markets. VTI has compounded at roughly double the rate of VXUS over that period.

The reasons are real: US tech dominance, stronger GDP growth, favorable dollar strength, and the outperformance of large-cap growth stocks. The S&P 500's weighting toward high-multiple tech companies has been a structural tailwind.

But here's the counterargument: past performance doesn't predict future performance, and the more something has outperformed, the higher its current valuation. As of early 2026, US equities trade at a significant premium to international equities on virtually every valuation metric (P/E, P/B, Shiller CAPE). That premium either reflects genuine quality or sets up a reversion.

The Case for International

Diversification. When you own only VTI, your portfolio's fate is tied to US policy, US economic cycles, and US corporate governance. Adding VXUS reduces single-country risk. Valuation. International equities are cheaper. Much cheaper. If you believe in mean reversion, that's an argument for expected higher future returns from international. Currency exposure. A weaker dollar -- which many economists consider likely given US debt levels -- would boost returns from international holdings when measured in dollars. Market-cap weighting. The US represents roughly 60-65% of global market cap. Owning only US stocks means you're making an active bet that the US will continue to dominate. A passive, market-cap-weighted investor should hold the whole world.

The Case Against (or for Less)

Home country simplicity. Many investors in US-centric careers already have implicit US exposure through their human capital. Adding more US makes some sense. Currency drag. International funds add currency risk. The dollar's safe-haven status means international returns in USD terms are dampened during global stress events. Tax complexity. Foreign tax credits help, but international dividends often carry higher tax complexity than domestic ones. 15 years of evidence. It's hard to hold an underperforming asset for 15 years and stay disciplined. Many investors added VXUS and watched it drag performance, then abandoned the allocation.

Common Allocation Frameworks

Market-cap weighted (~65/35): Closest to neutral. Own the world in proportion to its market cap. 70/30 US/Intl: Slight US tilt. Common among advisors. 80/20 US/Intl: Significant US tilt. Acknowledges US quality premium while maintaining some diversification. 100% VTI: Unapologetically US. Valid for investors who have genuinely thought through the trade-off.

There's no universally right answer. The key is having a reason for your split and sticking with it through underperformance.

What to Actually Do

If you're starting fresh: the simplest defensible approach is to pick an allocation you can hold for 30 years without abandoning it. If watching VXUS underperform for another decade would make you sell, own less of it.

If you're already holding VTI-only: ask whether you'd add VXUS today if you were starting from scratch. If yes, adding it gradually makes sense.

Compare Them Yourself

See how VTI and VXUS have tracked over the past 5 years, including drawdowns and recovery periods.

Compare VTI vs VXUS on StockResearch

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This post is for informational purposes only and does not constitute financial advice. Past performance does not guarantee future results. International investing involves currency and political risks not present in US-only portfolios.