FYI: If you stop the average investor walking down the street and ask him what a large-cap stock is, he might respond Apple (AAPL), Alphabet (GOOG), Amazon.com (AMZN), or maybe Bank of America (BAC). However, most investors would probably struggle to name a mid-cap stock, even though names like Burlington Stores (BURL), Tractor Supply (TSCO), and Whirlpool (WHR) may be familiar to them. Mid-cap stocks are often overlooked, and yet, over the past 15 years, they have outperformed both large- and small-cap stocks. There is no structural reason to justify this, nor is there a reason to believe it will continue. However, mid-cap stocks warrant more attention than they currently garner.
Regards,
Ted
https://www.morningstar.com/articles/946517/demystifying-us-mid-cap-indexing