Both are excellent — but there are real differences. Here\'s which one belongs in your portfolio.
VOO and VTI are the two most popular ETFs from Vanguard — and among the most widely held investments in the world. If you've done any research on index fund investing, you've almost certainly encountered both. So which is better?
VOO is the Vanguard S&P 500 ETF. It tracks the S&P 500 Index, holding the 500 largest publicly traded U.S. companies selected by a committee at S&P Dow Jones Indices. It launched in 2010 and has an expense ratio of just 0.03%. As of 2026, it manages over $500 billion in assets — making it one of the largest ETFs in existence.
VTI is the Vanguard Total Stock Market ETF. It tracks the CRSP US Total Market Index, holding virtually every publicly traded U.S. stock — approximately 3,600 companies. This includes all the S&P 500 stocks plus thousands of mid-cap and small-cap companies. It also has an expense ratio of 0.03%.
VOO tends to outperform during periods when large-cap stocks lead the market — which has been much of the past decade. When mega-cap tech companies like Apple, Microsoft, and NVIDIA surge, VOO benefits fully because they make up a larger proportion of its portfolio.
VTI tends to outperform when small-cap stocks rally — which happens periodically, often at the start of economic recovery cycles. Small-cap stocks historically have higher long-term returns than large-caps (the "size premium"), though with more volatility.
For most investors, the honest answer is: it doesn't matter. Choose one, invest consistently, and don't switch. Both will serve you extraordinarily well over decades. If you already own one and it's working for you, there's no reason to change. If you're starting fresh and want the broadest possible diversification, VTI gives you slightly more. If you prefer tracking the most widely followed benchmark, VOO is iconic.