Index and ETF: why charts of one market differ

Identify the measurement

A price index follows changes in constituent prices. A total-return index also incorporates income such as dividends under a specified reinvestment method. Gross and net-of-assumed-tax variants differ too. Record the precise index name, currency and return version.

NAV means net asset value per share: assets less liabilities divided by shares outstanding. An ETF share trades at a market price that may be above or below NAV. NAV itself is not a guaranteed execution price.

Compare one consistent period

Every series below is hypothetical and starts at 100. The fund makes no distributions to the holder during the period, has no flows and retains dividend income. Currency and dates match; personal trading fees and taxes are excluded. NAV and market values also represent hypothetical prices of one share here.

The fund’s NAV return is 9.5%, versus 10% for the total-return index: tracking difference is−0.5 percentage points. This is not automatically the expense ratio; holdings, costs, taxes and valuation timing can contribute. The closing market premium 109.8/109.5−1≈0.274% is a separate measurement, not that return gap.

Our own teaching example; all figures are hypothetical.

109.5 / 100 − 1 = 9.5%; 9.5% − 10% = −0.5 pp; 109.8 / 109.5 − 1 ≈ 0.274%

Record the identity before chart analysis

Keep the instrument, index variant, currency, closing time, distributions and data adjustment together. Compare returns only after aligning these conditions. Tracking error describes variability of return differences over multiple observations; one period’s gap does not measure it.

The SEC source covers specified US registered funds; other exchange-traded products need their own documentation. A gold fund is not the XAUUSD spot price. Elliott does not select ETFs or manage portfolios: the practical task here is to prepare the right input series.

SPY: real market bars, not NAV or an index chart

For the ETF class choose one explicit example: State Street SPDR S&P 500 ETF Trust, SPY, NYSEArca, USD, Yahoo timezone America/New_York. This is not every ETF or the S&P 500 index itself. We retain 17 provider OHLC rows for 1–23 October 2026, using Close on the same basis as O/H/L, not a separate Adj Close. At the 9 October replay cutoff C778.57 is inside U781.62,L758.79 from only 1–8 October. Retained later rows through the 23rd have no close above this U or below this L. This is a real bounded replay with retrospectively selected boundaries, not an established complete wave count or a forecast published earlier.

Prepared on 25 October 2026, the last SPY bar is the 23rd: O759.90,H763.47,L758.68,C759.97. Prior 1–22 October range: [758.79,781.62]. Low 758.68 is below L758.79, but close 759.97 is above L: strict C<L fails. Later completed closes are considered above 781.62, below 758.79 or inside separately. NAV and underlying index levels are not these market OHLC; synchronized NAV was not obtained, so no actual premium/discount is calculated. Neither a wick nor a range branch establishes an entire wave or profitability. Another ETF may differ in assets, currency, distributions and daily objectives; check its own documents and series again. For a selected ordinary cash-market impulse on SPY’s own price, check two<100% of one, three beyond one and not shortest among 1/3/5, four outside one’s territory, and internal 5–3–5–3–5. These tests require assigned anchors, absent here; matching an index or NAV cannot replace them.

• Price source: retained daily rows
• Price source: retained daily rows
• SPY issuer: fund and underlying index
• Yahoo: Close and Adj Close
• EWI: impulse and motive-wave definitions
• EWI: impulse and motive-wave definitions
• Shared conditional price-check worksheet

Sources

• SEC Investor.gov · Exchange-Traded Funds
• MSCI · How is an index constructed?
• SEC Investor.gov · Index Funds

Sources checked: 2026-10-21

This material and its translations were prepared with AI assistance. Educational calculations were checked programmatically. Sources explain concepts; examples and files were created for this article.

Related reading

• Benchmark: choosing a fair comparison for a result
• Asset currency and account currency: translating a return