Mid-sized US companies remain a useful tool for investing by company size. Ignored by cyclical traders, mid cap seems less volatile than small cap and less bid-up than large cap. But for most investors its job is to add diversification to a large cap portfolio.
Mid cap enthusiasts note that mid cap companies are good candidates for acquisition by larger ones, and when this happens shareholder receive a tidy premium. A quirk of index construction plays in mid cap's favor: the largest mid cap companies often get a speculative boost just before they are promoted to large cap index, once again to the benefit of shareholders.
Size definitions of mid cap companies by ETFs varies. Major plain-vanilla, low-cost mid cap ETFs with their size range of holdings include:
Fees range from Vanguard's tight-fisted .13% per year to as much as .25%, but all are reasonable. There is little expense drag to passive size investing in ETFs.
Where does mid cap start and end? Definitions vary by provider. For many investors the S&P 500 is synonymous with large cap, while the next 500 or so smaller stocks are mid cap and the next 2000 or so are small cap. Knowing how much to buy is crucial for over- or underweighting. In this case the first 500 stocks represent about 75% of the US stock market, the next 500 represent about a bit less than 15% and the next 2000 represent less than 10%. A size-neutral portfolio will allocate in these proportions.
Precise numbers for how much to invest in particular ETFs to remain neutral depends on each provider's definition of size boundaries. Allocations can be calculated by summing market capitalization and weightings of holdings of a provider's small, mid and large cap funds vs. the aggregate. Style investing takes a bit of work.
For investors seeking liquidity, IJH and EMM are good candidates. They themselves are quite liquid and complement S&P 500 ETFs which have tight bid-ask spreads due to their enormous trading volume, competitive fees and ample study by Wall St. analysts. They also are easy to follow in the news.
Note that EMM does not complement its sister products SPDR Dow Jones Wilshire Large Cap ETF (AMEX:ELR) and SPDR Dow Jones Wilshire Mid Cap ETF (AMEX:EMM). ELR contains stocks ranked 1-750 by size and is complemented by small cap ELR which handles stocks ranked 751-2500. Using EMM with them causes double exposure on mid cap stocks. EMM's true purpose is to complement S&P 500 ETFs such as SPY, which is useful for many investors.
In addition to these four plain-vanilla size-based ETFs, there are numerous mid cap ETFs also targeting growth or value:
For traders there are a handful of leveraged funds. They typically deliver two times the daily return of an index (or the inverse for the short funds), less costs of rolling over monthly futures. These deliver a bit more leverage than borrowing on margin from a broker, they cost less per unit of leverage, and losses are limited to your investment in the ETF (no late-night margin calls). A good deal all-in-all but strictly for traders.
Unlike large and small cap categories, however, only a few ETFs use fundamental financial ratios to beat popular indexes. These are high quality and at reasonable prices: