How to Invest in the S&P 500 (2026): VOO vs SPY vs IVV Compared

To invest in the S&P 500, you buy an exchange-traded fund (ETF) that tracks all 500 companies in that index. The three most popular options are Vanguard's VOO, State Street's SPY, and BlackRock's IVV, each holding identical stocks but differing in cost structure, liquidity, and account fit. For most buy-and-hold investors, VOO or IVV are the better choice; for options traders, SPY wins on liquidity alone.

The Three Main S&P 500 ETFs: Side-by-Side

Data as of October 1, 2026. Source: nerdwallet.com, etf.com

All three own the same 500 companies. So why do they differ at all, and why does anyone pay more for one than another? The answer lies in fund structure, trading liquidity, and hidden costs that compound over decades.

Understanding the Cost Differences: More Than Just the Expense Ratio

The expense ratio is the annual fee the fund charges, but it tells only part of the story. VOO and IVV charge 0.03% and SPY charges 0.0945%, meaning on a $10,000 position, you pay $3 per year (VOO or IVV) or $9.45 per year (SPY). Over time, this difference compounds. On a $100,000 balance, the 0.06 percentage point fee gap has historically meant roughly $3,941 in underperformance over 10 years.

The deeper difference is structural. SPY is a unit investment trust (UIT), a legal framework from the 1930s that prevents SPY from reinvesting dividends immediately. Instead, dividends sit in a non-interest-bearing cash account and are distributed to shareholders quarterly, creating "dividend drag". VOO and IVV, by contrast, are open-end funds that reinvest dividends right away, keeping all capital fully invested. In rising markets over long periods, this structural advantage compounds to a real edge.

In practice, VOO has trailed the S&P 500 by only 0.04 percentage points, essentially in line with its 0.03% fee, while SPY has trailed by 0.14 to 0.16 percentage points, wider than its stated fee alone would suggest. The gap, while small in any given year, is real and measurable across many market cycles.

When Liquidity Matters: Trading vs Holding

For investors who buy and hold, liquidity is irrelevant. On a $5,000 monthly position, the bid-ask spread difference between SPY, VOO, and IVV is fractions of a cent. It simply will not affect your returns.

For active traders and options users, SPY dominates. SPY trades $40-50 billion daily on average, more than seven times VOO's $3-5 billion. More importantly, SPY accounts for 99.2% of options open interest among S&P 500 ETFs. This means covered call strategies, protective puts, and other derivatives strategies are cheaper, faster, and more flexible to execute on SPY than on any alternative. If you plan to write covered calls or hedge with options, SPY's unmatched derivatives ecosystem justifies paying the higher fee.

Tax-Loss Harvesting: A Strategy for Taxable Accounts

One subtle tool many investors overlook is tax-loss harvesting, where you sell a fund at a loss to offset capital gains elsewhere in your portfolio, then immediately buy a similar fund to maintain your market exposure. Because VOO and IVV are functionally identical but legally separate funds, you can sell one at a loss and immediately buy the other without triggering wash sale rules. This flexibility is one reason holding VOO in some accounts and IVV in others can make sense, especially for larger portfolios.

The Practical Decision Framework

For a new investor in a taxable brokerage account buying once a month, start with VOO or IVV. The 0.03% expense ratio is the lowest available for a broad S&P 500 ETF, the open-end structure avoids dividend drag, and both are highly tax-efficient, historically making zero or near-zero capital gains distributions. Between the two, the choice is personal. VOO has crossed $1 trillion in assets under management, making it the default choice for retail investors in Vanguard accounts. IVV is the equivalent choice for Fidelity and Schwab users, and offers flexibility for tax-loss harvesting in non-Vanguard accounts.

If you already own SPY in a taxable account, calculate the tax bill on selling it against the return gap. On a large position, that tax bill can exceed years of fee savings. In a retirement account like an IRA where sales are not taxed, the math is clearer: the return gap decides it, and new money belongs in VOO or IVV. If you trade options, SPY's liquidity premium is worth the higher fee.

You can use MinMaxDoc to compare the performance and allocation of these funds within a mock portfolio, allowing you to see how the expense ratio and structural differences play out across different time horizons and investment amounts before committing real capital.

FAQ

Does it matter which S&P 500 ETF I own if I'm buying and holding for 20+ years?

Over very long periods, the expense ratio difference becomes the main driver. On a $50,000 initial investment growing at 7% per year for 20 years, the 0.0645% gap between SPY and VOO/IVV compounds to several thousand dollars. If you're already in one and it's in a taxable account, the tax bill to switch may overwhelm the benefit. If you're starting fresh, VOO or IVV edges out SPY.

Can I hold all three to get better diversification?

No. All three hold identical stocks. Holding multiple S&P 500 ETFs adds complexity and trading costs without additional diversification. Pick one and invest the rest elsewhere.

Is SPYM (0.02% expense ratio) a better deal than VOO at 0.03%?

SPYM has a lower stated fee, but it is newer and less established than VOO. For most investors, the 0.01% difference ($1 per $10,000) is noise. VOO's $1+ trillion in assets, longer track record, and Vanguard's mutual-fund-owned structure offer more assurance. If you want to optimize to the penny and SPYM is available in your brokerage, it is a valid choice.

How often should I rebalance or check my S&P 500 holding?

Once or twice per year is enough for a core buy-and-hold position. Frequent trading incurs bid-ask spreads and can disrupt dollar-cost averaging. Set your contribution schedule and let compounding work.

Disclaimer: This content is for educational and informational purposes only and does not constitute financial, investment, or tax advice. The information presented reflects the author's opinions and analysis at the time of writing and may not be suitable for your individual circumstances. Always consult with a qualified financial advisor before making investment decisions. Past performance is not indicative of future results. MinMaxDoc and its authors are not registered investment advisors.