What Is IVOO? Vanguard S&P Mid-Cap 400 Index Fund ETF Shares
Last updated July 2026
Short answer
IVOO is Vanguard S&P Mid-Cap 400 Index Fund ETF Shares, an ETF that tracks a US mid-cap equity index at a 0.07% expense ratio. IVOO tracks a US mid-cap equity index. It launched in 2010. The distribution yield is about 1.16%. At 0.07% it undercuts the typical mid-cap blend fund, which runs nearer 0.23%. Holdings are spread widely, with the ten largest coming to about 8% of assets.
IVOO is issued by Vanguard and tracks a US mid-cap equity index. It charges a 0.07% expense ratio, holds approximately $5.9B in assets under management, yields about 1.16%, and launched in 2010.
What is IVOO?
IVOO is Vanguard S&P Mid-Cap 400 Index Fund ETF Shares, an ETF that tracks a US mid-cap equity index at a 0.07% expense ratio. IVOO tracks a US mid-cap equity index. It launched in 2010. The distribution yield is about 1.16%. At 0.07% it undercuts the typical mid-cap blend fund, which runs nearer 0.23%. Holdings are spread widely, with the ten largest coming to about 8% of assets.
IVOO is issued by Vanguard and tracks a US mid-cap equity index, so a single ticker gives you the whole portfolio of underlying holdings weighted by the index's methodology rather than by any active stock-picking.
What does IVOO hold?
IVOO is weighted toward its largest constituents. As of August 2026, the top holdings are:
| Rank | Ticker | Company | % of IVOO | |
|---|---|---|---|---|
| 1 | TWLO | Twilio Inc Class A | 0.9% | |
| 2 | CRS | Carpenter Technology Corp | 0.8% | |
| 3 | MKSI | MKS Inc | 0.8% | |
| 4 | CW | Curtiss-Wright Corp | 0.8% | |
| 5 | ENTG | Entegris Inc | 0.7% | |
| 6 | NVT | nVent Electric PLC | 0.7% | |
| 7 | ATI | ATI Inc | 0.7% | |
| 8 | ILMN | Illumina Inc | 0.7% | |
| 9 | FTI | TechnipFMC PLC | 0.7% | |
| 10 | STRL | Sterling Infrastructure Inc | 0.7% |
The remaining holdings make up the balance of the fund, with weights tapering off below the top names. Because the index reconstitutes on a rolling basis, the roster stays current without active management. Each ticker above links to its individual stock guide in Walnut.
How do I invest in IVOO?
There are three common ways to get IVOO exposure. Buy shares (or fractional shares) of IVOO directly at any major broker that lists it. Hold it as a core position and layer more concentrated ideas on top. Or build it into a thematic portfolio in Walnut, so IVOO sits alongside other holdings that express the same thesis, with target weights you can rebalance toward. IVOO trades like a stock during market hours, so you buy it the same way you would any listed share.
New to buying funds? See how to buy an ETF, step by step.
Is IVOO a good buy?
Whether IVOO is a good buy depends less on any single call and more on your time horizon and what you already hold: it tracks a US mid-cap equity index, so the real question is whether you want that exposure in your mix and at what weight. We walk through valuation, concentration, and what would have to be true for it to outperform from here in is IVOO a buy?
The bottom line on IVOO
IVOO gives you a US mid-cap equity index exposure in one ticker at a 0.07% expense ratio. Most investors use it as a core holding and layer more concentrated thematic portfolios on top.
More on IVOO
Whether IVOO is worth buying today depends more on your time horizon and what you already hold than on any single call. We walk through valuation, concentration, and what would have to be true for it to outperform from here in is IVOO a buy?
IVOO yields 1.16% as of August 2026, paid by passing through the dividends of its underlying holdings. For the payout schedule, history, and how the distributions are taxed, see IVOO dividend: yield and schedule.
New to funds like IVOO? Start with what an ETF is, then how to buy an ETF, or browse the full guide to ETF investing.
Wondering how IVOO fits the portfolio you already own? Walnut is an AI investing app that connects your brokerage read-only and answers questions like that about your actual holdings: overlap, concentration, and how each position tracks the S&P 500. Compare the best AI portfolio analyzers or see the best AI investing apps in 2026.
Investing in IVOO with AI
Connect the broker you already use and ask Walnut's AI how IVOO fits what you actually hold: what it overlaps with, what it leaves you exposed to, and how it has tracked the S&P 500. Read-only by default, and you approve anything before it reaches your broker.
FAQ
What is IVOO's ticker symbol?
+
IVOO, Vanguard S&P Mid-Cap 400 Index Fund ETF Shares. Issued by Vanguard; tracks a US mid-cap equity index. Trades during US market hours, available at every major US brokerage.
What is IVOO's expense ratio?
+
0.07% as of August 2026.
What are IVOO's top holdings?
+
Top holdings as of August 2026: TWLO, CRS, MKSI, CW, ENTG and others. See the full holdings table above.
How can I invest in IVOO through Walnut?
+
Walnut isn't a broker. Connect a brokerage and Walnut sits on top to help you build and track thematic portfolios. IVOO can be a constituent alongside individual stocks.
How do I compare IVOO to similar ETFs?
+
Put a few fields side by side: the expense ratio (fees compound over decades), the index or strategy it tracks, the top holdings and how much they overlap with what you already own, the dividend yield, and the AUM, liquidity, and bid-ask spread that affect trading costs. For index funds, tracking error (how closely it follows its index) and tax efficiency matter too. IVOO's figures are above; the full method is in Walnut's guide on how to compare ETFs.
Related ETFs
Walnut is informational, not investment advice. Holdings weights and fund statistics on this page are approximations stamped to August 2026; verify current figures against Vanguard's fund page or your broker before investing.