What Is VO? Vanguard Mid-Cap ETF

VO is the Vanguard Mid-Cap ETF, tracking the CRSP US Mid Cap Index at a 0.03% expense ratio. It holds roughly 300 mid-cap US companies in a market-cap-weighted portfolio, giving single-ticker exposure to the middle of the US market, the stocks that sit between large-cap leaders and small-cap names.

Vanguard launched VO in January 2004, and it has grown into the largest mid-cap fund by assets, with roughly $105 billion across its share classes. Its pitch is low cost, broad diversification, and a long track record.

Approximate weights as of mid-2026; refresh quarterly from Vanguard's fund page. Each ticker links to its individual stock guide in Walnut.

VO holds around 300 stocks led by names like Seagate Technology, Western Digital, Vertiv, Quanta Services, and Howmet Aerospace, each roughly 1% to 2% of the fund. The ten largest holdings are about 10% of assets, so the portfolio is diversified but a bit more concentrated at the top than a small-cap index.

Sector exposure spans industrials, technology, financials, and energy, with less weight in the mega-cap technology stocks that dominate the S&P 500. That mix is why mid-cap funds can behave differently from broad large-cap indexes over a given cycle.

VO and IJH are the two dominant mid-cap ETFs. VO tracks the CRSP US Mid Cap Index, which defines the segment by a percentage band of total market cap. IJH tracks the S&P MidCap 400, which uses fixed size ranges and requires companies to be profitable to enter. VO charges 0.03% versus IJH's 0.05%.

The S&P 400's profitability screen has at times given IJH a modest quality tilt, while VO's index reaches a slightly different set of names at the size boundaries. In practice the two track closely. VO's edge is a marginally lower fee and Vanguard's scale; IJH's edge is the profitability screen. Neither is objectively better, and the right choice depends on which index methodology you prefer.

VO's returns closely follow the mid-cap segment, minus its small fee. Mid-caps have historically delivered competitive long-run returns, sometimes outpacing both large- and small-caps over long stretches, with volatility that sits between the two.

As a passive index fund, VO's outlook is the outlook for US mid-cap stocks as a group. It tends to lag when a handful of mega-caps drive the market and can outperform when breadth widens and mid-sized companies lead.

VO suits investors who want to fill the mid-cap gap that S&P 500 and small-cap funds leave open, at minimal cost. It commonly serves as a core diversifier sized alongside a large-cap holding rather than as a standalone portfolio.

Whether VO fits depends on your time horizon, risk tolerance, and existing exposures. Walnut is not an investment adviser, and this is not a recommendation to buy VO. It is a description of the fund and the role it typically plays.

VO trades on every major US brokerage, including Robinhood, Fidelity, Schwab, and Public, usually commission-free and often with fractional shares so you can invest a fixed dollar amount. Its deep liquidity keeps trading spreads tight.

To hold VO alongside a stated thesis, connect your broker to Walnut and track it inside a themed basket. Walnut mirrors your real positions and shows how they map to your targets, while trade execution stays at your broker.

The bottom line on VO: a cheap, diversified way to own the mid-cap slice of US stocks that broad large-cap funds underweight. At 0.03% it is a touch cheaper than IJH, and its 300 holdings sit between small-cap and large-cap indexes. It plays a core diversifier role, filling the gap between an S&P 500 fund and a small-cap position.

Whether VO 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 VO a buy?

VO yields ~1.3% as of mid-2026, paid by passing through the dividends of its underlying holdings. For the payout schedule, history, and how the distributions are taxed, see VO dividend: yield and schedule.