S&P MidCap 400

The S&P MidCap 400 Index, more commonly known as the S&P 400, is a from S&P Dow Jones Indices. The index serves as a barometer for the U.S. mid-cap equities sector and is the most widely followed mid-cap index in existence. To be included in the index, a stock must have a total market capitalization that ranges from $1.4 billion to $5.9 billion at the time of addition to the index. As of 31 January 2017^[update], the median market cap was almost $3.8 billion with the market cap of the largest company in the index at more than $10.6 billion and the smallest company at $948 million. The index's market cap covers nearly 7 percent of the total US . The index was launched on June 19, 1991.

It has set a series of all-time highs since the Federal Reserve announced its third round of recent quantitative easing in mid-September 2012. At the weekly and monthly close of November 30, 2012, the index settled at the 1,000 point mark, and it has continued to rise in early 2013, setting new records above 1,200 by mid-May.

The following exchange-traded funds (ETFs) attempt to track this index and sub-indexes:

The SPDR fund was first, but the iShares fund is bigger; also they have different structures.

The "S&P 400" generally quoted is a price return index; there are also "total return" and "net total return" versions of the index. These versions differ in how dividends are accounted for. The price return version does not account for dividends; it only captures the changes in the prices of the index components. The total return version reflects the effects of dividend reinvestment. Finally, the net total return version reflects the effects of dividend reinvestment after the deduction of withholding tax.

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