This article mentions funds that have an issuer-initiated rating and/or track a Morningstar Index. For full disclosure information, please refer to the specific funds, which are demarcated with a * symbol, listed below.
Key Morningstar Metrics for Vanguard Mid-Cap Index Fund
- Morningstar Medalist Rating: Gold
- Process Pillar: High
- People Pillar: Above Average
- Parent Pillar: High
Vanguard Mid-Cap Index Fund offers inexpensive and diversified exposure to US mid-cap stocks, carving a durable advantage in this efficient market segment.
The fund replicates the CRSP US Mid Cap Index, which selects stocks that land between the 70th and 85th percentile of the US stock market by market capitalization. Holdings are market-cap weighted and must meet the minimum size and liquidity criteria. Buffers around size thresholds reduce unnecessary turnover. Each quarterly rebalance and reconstitution is spread across five days to minimize the market impact and further reduce trading costs.
Market-cap weighting forms the bedrock of this fund, which harnesses the market’s collective wisdom on the relative value of each holding. It’s also keeps turnover and associated trading costs down. Mid-cap stocks reflect new information quickly since most trade frequently. On average, passive funds in the mid-cap blend Morningstar Category have outperformed their active peers over the long run.
Sector allocations have been a reasonable approximation of peers. They deviated by no more than 5 percentage points from the average mid-blend fund at the end of May 2025. The portfolio was less concentrated and typically holds about the same number of stocks as peers. Less concentration means the portfolio is less affected by individual stock movements, which can keep volatility in check.
The portfolio tilts toward large-cap stocks relative to other funds in its category. Different index families define mid-cap stocks differently, leading to a wide range of portfolios across index funds in the mid-blend category. Investors should consider these differences when building a portfolio. Staying within the same index family can reduce gaps or overlap between market segments.
Vanguard Mid-Cap Index Fund: Performance Highlights
The fund has capitalized on its low fee and low transaction costs by effectively tracking the mid-cap market segment. The ETF share class outperformed its average peer in the mid-cap blend category by 1.76 percentage points annualized since its January 2004 inception through June 2025. The fund notched better risk-adjusted performance despite higher volatility.
The fund’s performance fluctuated slightly more than its average peer, although the gap has narrowed in recent years. Staying invested helps during rallies but can hold this fund back in broad declines compared with active funds that possess a cash buffer.
It’s possible for the portfolio to lose more than the average mid-blend fund when the market falters. For example, the ETF share class lost 18% in 2022: 4 percentage points worse than the average mid-blend fund, which lost only 14%. The fund’s heavier stake in technology stocks was to blame, since they fell more than the rest of the market. However, 2022 was an anomaly. The fund leans toward larger stocks, which means drawdowns are usually less pronounced.
Overall, the fund’s performance should resemble that of the mid-cap market. Its large-cap bias could protect it from some volatility, but its low cash drag can negate that benefit. Its low fee and low turnover should give it an edge over pricier peers that trade more often.
The author or authors do not own shares in any securities mentioned in this article.
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