Most ETFs Track Index Returns Very Well

ETFs replicate index exposure through portfolio construction and arbitrage (creations/redemptions) so that, when trading hours align, ETF daily returns closely match their indexes — exemplified by U.S. products like QQQ and RSP. International ETFs such as FXI often show much larger daily return deviations not because of mispricing or poor management but because underlying markets close in different time zones and news flows occur outside local trading hours; these intraday differences can even produce opposite daily moves for the index and the ETF. Over longer horizons or when returns are measured on comparable time windows (tracking difference or annualized standard deviation of daily differences), most ETFs track their benchmarks well. For investors, the practical takeaway is to evaluate international ETF performance using tracking-difference metrics rather than raw same-day return comparisons, noting that market makers and portfolio managers generally keep ETFs closely aligned with underlying values.

Analysis

Index-tracking ETFs replicate benchmark exposure via portfolio construction and arbitrage mechanisms — notably creations and redemptions and active market makers — so that when trading hours align the ETF price and the underlying portfolio move in near lockstep (Chart 1 and Chart 2). Empirical data in the article shows large, liquid U.S. products such as QQQ and RSP exhibit almost identical daily returns and tight bid-offer behavior even on days the ETF itself does not trade, indicating low daily tracking error.

International ETFs, exemplified by FXI, display materially larger daily deviations and frequent dots off the diagonal in Chart 2, sometimes moving opposite the local index on a given day; the article attributes this primarily to asynchronous close times and continuous news flow rather than mispricing or poor management. The note highlights that U.S. ETFs report returns on a U.S. close-to-close basis, international indices on local close-to-close, and that 24-hour instruments like S&P futures on the CME can move independently outside local market hours (Chart 4).

Tracking error is defined here as the annualized standard deviation of daily ETF-minus-index return differences (Chart 3), while tracking difference (multi-day or annual return comparison) removes timing mismatches. Chart 5 shows that over longer windows FXI and other international ETFs still closely follow their benchmarks, so investors should judge international ETF performance with tracking-difference metrics and account for time-zone, liquidity and arbitrage constraints rather than headline daily divergences.

Key Decisions for Investors

• Use tracking-difference or annualized tracking-error metrics rather than same-day return comparisons when evaluating international ETFs such as FXI
• Favor large, liquid U.S. ETFs like QQQ and RSP for strategies requiring tight intraday tracking and low bid-offer spreads
• Monitor underlying market close times and 24-hour price signals (e.g., S&P futures on CME) to anticipate overnight moves in internationally-exposed ETFs and consider hedging overnight exposure
• Do not assume daily opposite moves imply mispricing; instead assess creation/redemption capacity, liquidity and longer-horizon tracking performance before adjusting positions