Mid-cap stocks are tracked by multiple indexes, with the S&P Mid-Cap 400 being the most commonly referenced, alongside the Russell Midcap and Wilshire US Mid-Cap Index. These indexes serve as benchmarks for investors seeking exposure to mid-sized companies, which typically have market capitalizations between $2 billion and $10 billion, as defined by FINRA. 

For investors looking to track mid-cap performance, popular ETFs include the iShares Core S&P Mid-Cap ETF (IJH), Vanguard Mid-Cap Index ETF (VO), and iShares Russell Mid-Cap ETF (IWR). IJH follows the S&P MidCap 400 Index, holding companies like Williams Sonoma and Interactive Brokers, with a strong weighting in industrials and financials. 

Vanguard’s VO, which mirrors the CRSP US Mid Cap Index, includes firms such as Welltower and Palantir Technologies, while IWR, aligned with the Russell MidCap Index, features holdings like Applovin and Williams Inc.

Finsum: Mid-cap investments offer a middle ground between the stability of large caps and the growth potential of small caps, making them an attractive option for investors aiming to diversify their portfolios.