Vanguard Mid-Cap Index Fund Admiral Shares VIMAX

Vanguard Mid-Cap funds offer 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.

The bedrock of this strategy is market-cap weighting, which harnesses the market’s collective wisdom on the relative value of each holding. It’s also an efficient approach, keeping turnover and associated trading costs down. Mid-cap stocks reflect new information quickly since most are frequently traded. On average, passive funds in the mid-cap blend Morningstar Category have outperformed their active peers over the long run.

Sector allocations are a reasonable approximation of peers. Sector weights deviated by no more than 5 percentage points compared with the average mid-blend fund, as of May 2025. The portfolio is less concentrated and typically holds about the same number of stocks as peers. Lower 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. Investors should consider these differences when building a portfolio. Staying within the same index family can reduce gaps or overlap between market segments.

The exchange-traded fund share class outperformed its average peer by 1.72 percentage points annualized over the past 10 years through June 2025. Low fees, low turnover, and little cash allow the fund to capture its slice of the mid-cap universe with minimal performance drag. Staying fully invested means the fund can underperform when mid-cap stocks fall, but it should be a long-term benefit, helping it capture nearly all its index’s returns.

This strategy accurately captures its slice of the mid-cap market and keeps a lid on turnover by leveraging the market’s collective wisdom to size its positions. It earns a High Process Pillar rating.

The CRSP US Mid Cap Index targets stocks between the 70th and 85th percentile of the total US market capitalization and weights them by market cap. Constituents must meet certain liquidity and size requirements to ensure they can be traded efficiently. Buffers at each size threshold reduce turnover and transaction costs by prioritizing existing holdings. Spreading its quarterly reconstitution and rebalance process over five days further minimizes trading costs and reduces market impact.

Market-cap weighting makes sense in the mid-cap blend category. Market-cap weighting relies on the market’s collective wisdom to determine the relative value of each holding. In addition, it can reduce transaction costs since holdings’ weights automatically adjust when their prices fluctuate. While not as efficient as the highly liquid large-cap market, mid-cap stocks also generally reflect information quickly, meaning it’s harder for active managers to gain an edge. Actively managed strategies in the mid-blend category tend to underperform their passive peers in the long run.

The index selects larger stocks than most. Its average market cap was around USD 36 billion at the end of May 2025, which was about USD 22 billion larger than the average mid-blend fund. Larger stocks are generally less volatile, so the portfolio could exhibit lower volatility than its peers. Although, the lack of a cash buffer may negate any benefit. Size discrepancies can lead to divergent performance between the portfolio and its category peers.

Sector allocations reasonably approximate the category average, and the portfolio is well diversified. Like the average peer, this fund leaned into industrials stocks and away from communication-services stocks, as of May 2025. While sector weights generally follow the category norm, the portfolio is less concentrated. It held 9% in its top 10 holdings, about 6 percentage points less than the average mid-blend fund at the end of May 2025. Spreading risk across hundreds of holdings shields the portfolio should one or a few holdings falter.

Vanguard's equity index group earns an Above Average People Pillar rating for its well-supported and stable management team adept at leveraging Vanguard's comprehensive resources. Its portfolio managers benefit from the firm's global infrastructure and advanced portfolio-management technology, which facilitates cost-efficient trading around the globe. The infrequent turnover of managers, coupled with Vanguard's practice of rotating them across various funds, enhances their expertise and understanding of different market segments.

The fund's managers directly handle trading, providing them with deeper insights into the portfolio's operations than a stand-alone trader might have. They are backed by a global team of dedicated personnel and employ sophisticated, scalable technology to minimize their workload and enhance tracking accuracy. Vanguard's independent risk-management team plays a crucial role in ensuring its funds adhere to predetermined tracking tolerances. It collaborates closely with the managers to oversee trades and address potential issues proactively. Vanguard compensates managers based on tracking error and excess return metrics to foster a culture of accountability and ensure that the management team's interests are closely tied to investors'.

Vanguard maintains its High Parent Pillar rating as it continues to grow under new leadership.

CEO Salim Ramji has had a busy first year captaining Vanguard’s crew, and the ship remains pointed in the right direction. The firm made its largest round of fee cuts in early 2025, which came at an estimated cost of USD 350 million. It established a separate division dedicated to its advice and wealth management efforts, a sign that it wants to seriously compete within those lines of business. Asset growth has continued to be a huge success. Only BlackRock’s inflows rival the money Vanguard is taking in. Likewise, the number of clients it serves has more than doubled since 2015.

Despite that success, an ever-growing number of clients has presented a challenge: Vanguard can’t grow its services fast enough to keep up with demand. In some instances, it has had to curb certain services and capabilities or raise fees on others to cope, causing some loyal clients to criticize what they perceive as deteriorating services.

Vanguard has ambitions to bring its disruptive legacy to the bond market. It created roughly a dozen low-cost bond exchange-traded funds for US investors and several others abroad over the 12 months through June 2025. All have low fees in their respective categories, and the actively managed strategies align with Vanguard’s philosophy. They are relatively easy to understand and are conservatively managed.

Vanguard has another opportunity to prove that clients are still its priority. On the surface, its endeavor into the high-fee deal-making world of private assets alongside Wellington and Blackstone looks like a cultural mismatch. So far, the collaboration hasn’t produced anything that’s concerning.

The fund has capitalized on its low fee and low transaction costs by effectively tracking its slice of the mid-cap stock 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 ETF 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, the fund’s large-cap bias means drawdowns are usually less pronounced, making 2022 an anomaly.

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.

Vanguard Mid Cap Index Admiral's Prospectus Adjusted Expense Ratio is 0.05% per year. It places it in the cheapest quintile of the Morningstar US Fund Mid-Cap Blend Category, where the median fee is 0.83% per year. This cost positioning translates into a Medalist Rating Price Score of 2.23, which reflects its relative price positioning within the category. The Price Score ranges from -2.50 (most expensive) to +2.50 (cheapest), with higher scores indicating better cost competitiveness.