SPY vs VOO: Same Index, $9.45 or $3 a Year per $10,000

SPY (the State Street SPDR S&P 500 ETF Trust) and VOO (the Vanguard S&P 500 ETF) both follow the S&P 500, an index of about 500 large US companies. An ETF is a fund whose shares trade on a stock exchange. The two differ in fee and legal structure.

Over 16 years, $10,000 grew to almost the same amount in each. The figures are $91,943 in SPY and $92,856 in VOO, with dividends counted as reinvested. We took the fee and structure facts from the issuers' own pages, read on 27 October 2026.

Both funds hold the shares in the S&P 500 Index. The index weights each company by the market value of the shares available to the public, a method called float-adjusted market capitalisation. A larger company gets a larger weight.

State Street's page shows SPY with 504 holdings on 26 October 2026, while Vanguard's shows 505 securities in VOO at 30 September 2026. Some companies hold more than one line, such as Alphabet's Class A and Class C shares.

VOO uses full replication, which means it holds all the index's stocks in the index's weights. That is the method Vanguard's page states.

Our explainers on what an ETF is and what an index fund is cover the basics.

An expense ratio is the yearly cost taken from a fund's assets, shown as a share of those assets. SPY's is 0.0945%, from State Street's fund page and its 30 September 2026 fact sheet. VOO's is 0.03%, from Vanguard's page, dated 28 April 2026.

On $10,000, that is $9.45 a year for SPY and $3.00 for VOO. The gap is $6.45 a year. Chart 1 adds IVV (the iShares Core S&P 500 ETF), a third fund on the same index, at 0.03% on iShares' page.

Chart 1 shows SPY costing about three times as much each year as the other two funds.

SPY is a unit investment trust registered under the Investment Company Act of 1940. Its prospectus sets three limits. The trust provides no dividend reinvestment service. It may not lend its securities. It may not hold derivatives such as futures, options or swaps.

SPY pays dividends quarterly. A holder who wants them reinvested depends on the firm holding the shares. The prospectus says such firms offer the service at their own discretion.

VOO is an exchange-traded share class of Vanguard 500 Index Fund. A share class is one of the ways to hold the same fund. VOO is the one that trades on an exchange.

State Street shows SPY with $810.0 billion in assets on 26 October 2026. Vanguard shows the VOO share class at $1.0 trillion on 30 September 2026, inside a fund of $1.7 trillion across all its share classes. The dates differ, so we do not rank the two.

SPY listed on 22 January 1993. VOO's inception date is 7 September 2010, which is why our two-fund tests start that month. Our price files hold no IVV series, so the tests cover SPY and VOO only.

The bid-ask spread is the gap between the price a buyer offers and the price a seller asks. Its 30-day median is 0.00% for SPY and 0.004% for VOO, on the issuers' pages. Our explainer on the bid-ask spread covers the term.

A $10,000 stake in SPY on 9 September 2010 became $91,943 by 26 October 2026, an annual rate of 14.75%. In VOO it became $92,856, or 14.82% a year. VOO ended 0.99% above SPY.

Chart 2 shows the two lines almost on top of each other. VOO ends $913 higher.

The window is 4,057 trading days over 16.1 years. The funds' daily returns have a correlation of 0.9986. Correlation measures how closely two series move together, where 1 means perfectly in step.

On 86.6% of days the two returns differed by 0.05 percentage points or less. The median daily gap was 0.02 percentage points.

The largest daily gap came on 9 April 2025. SPY rose 10.50% and VOO rose 9.27%, a gap of 1.23 percentage points. Nine of the ten largest daily gaps were followed by a gap in the opposite direction the next day.

A calendar year here runs from the last close of the year before to the last close of the year. VOO led in 13 of the 15 full calendar years from 2011 to 2025, by 0.01 to 0.17 percentage points. SPY led in two years: 2020 by 0.08 and 2022 by 0.01.

Chart 3 shows each year's gap. 2010 runs from 9 September and 2026 to 26 October, so both are part years.

The current fee gap is 0.0645 percentage points a year. Over 16.1 years that adds up to about 1.04 percentage points. The ending values differ by 0.99%, a different measure: VOO's value divided by SPY's, minus one.

A fall from a high is how far the price dropped below its highest earlier close. We took the largest fall inside a window fixed in advance, with dividends counted. The last column of the table is the first close at or above that high, searched through 26 October 2026.

Largest fall from a previous high inside the window, with dividends counted. VOO's high, low and back-at-the-high dates match SPY's in the four episodes where it was listed. Source: YX Insights price data

Chart 4 shows the largest fall in each episode for both funds. In the four falls where both existed, the high, the low and the back-at-the-high dates matched.

The size of the fall differed by 0.31 percentage points in March 2020 (34.01% for VOO against 33.70% for SPY). It differed by 0.03, 0.04 and 0.07 percentage points in the other three.

SPY alone covers 2007 to 2009. It fell 55.20% from 9 October 2007 to 9 March 2009. From the 2007 high, getting back to it took 1,224 trading days, until 16 August 2012. VOO was not listed then.

Our study of how ETFs behaved across seven shocks puts 27 funds through similar episodes.

The fee gap costs a $10,000 holder $6.45 a year. The files show only the total gap of $913, not how much of it is the fee.

The tests above count dividends as reinvested on the day the price drops for them. SPY's trust provides no reinvestment service. We also measured the opposite case: dividends paid out as cash and held uninvested, with no interest.

In that case $10,000 became $76,457 in SPY and $77,134 in VOO, from 9 September 2010 to 26 October 2026. That is $15,486 less than the reinvested figure for SPY and $15,722 less for VOO. The gap between the two funds shrinks to $677.

The test covers one 16.1-year window in the past. It makes no forecast. It leaves out dealing costs and tax.

SPY and VOO follow one index, so their prices moved almost as one. The fee and the legal structure are where they differ.

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SPY is a unit investment trust, a fixed fund structure that follows rules set when it was created. It charges 0.0945% a year. VOO is a share class of a Vanguard fund and charges 0.03%. Both follow the S&P 500 Index. SPY's prospectus says the trust provides no dividend reinvestment service.

VOO has the lower fee. Its expense ratio, the yearly cost taken from the fund's assets, is 0.03%, against 0.0945% for SPY. On $10,000 that is $3.00 a year against $9.45. The iShares Core S&P 500 ETF (IVV), a third fund on the same index, also shows 0.03% on iShares' page.

Almost. From 9 September 2010 to 26 October 2026, with dividends counted as reinvested, $10,000 became $91,943 in SPY and $92,856 in VOO. That is 14.75% and 14.82% a year. The daily returns of the two funds have a correlation of 0.9986, where 1 means perfectly in step.

SPY is an exchange-traded fund (ETF), a fund whose shares trade on an exchange. Its legal form is a unit investment trust registered under the Investment Company Act of 1940. VOO is an exchange-traded share class of Vanguard 500 Index Fund. Our explainer on mutual funds against ETFs covers the difference.

DISCLAIMER: This article is strictly educational. Any information or analysis in this note is not an offer to sell or the solicitation of an offer to buy any securities. Nothing in this note is intended to be investment advice and nor should it be relied upon to make investment decisions. Any opinions, analyses, or probabilities expressed in this note are those of the author as of the note's date of publication and are subject to change without notice.