VOO vs SPY
Both VOO and SPY aim to track the S&P 500 index. Here's how they differ and what's worth checking before choosing between them.
What they have in common
VOO and SPY both aim to track the S&P 500 index, meaning their underlying holdings — roughly 500 large U.S. companies — are very similar. Because of this, their day-to-day price movements tend to track each other closely.
Fund structure
VOO is an open-end fund managed by Vanguard. SPY is structured as a unit investment trust (UIT), one of the oldest ETF structures, managed by State Street. This structural difference affects some technical details, such as how each fund can handle dividends internally and whether it can lend out securities it holds.
Expense ratio and share price
Expense ratios and share prices for both funds can change over time, and either fund may have a lower cost or lower share price at any given moment. Rather than relying on a fixed number here, check the current expense ratio and share price directly on Vanguard's and State Street's official fund pages before comparing.
Liquidity and trading
SPY has historically been one of the most actively traded ETFs in the world, with a deep options market, which is part of why it's popular with active traders and institutions. VOO is also highly liquid and widely held, particularly by long-term, buy-and-hold investors, but its options market and trading volume have generally been smaller than SPY's.
Which one is "better"
Since both funds track the same index, the choice often comes down to factors like cost, whether you value SPY's deep options liquidity, and which platform or brokerage you're using. This is an area where individual circumstances matter — this page is educational and not a recommendation to buy either fund.
Want to project growth for either fund under your own assumptions? Use our VOO calculator — the same compound-growth math applies regardless of which S&P 500 fund you hold.