S&P MidCap 400

S&P MidCap 400
Name	S&P MidCap 400
Foundation	1991
Operator	S&P Dow Jones Indices
Exchanges	New York Stock Exchange, Nasdaq
Constituents	400
Cap	Mid-cap
Website	https://www.spglobal.com/spdji/en/indices/equity/sp-400

S&P MidCap 400 is a stock market index maintained by S&P Dow Jones Indices that measures the performance of mid-sized companies in the United States. It serves as a key benchmark for the mid-cap segment of the U.S. equity market, distinct from the large-cap focus of the S&P 500 and the small-cap orientation of the S&P 600. The index is widely used by institutional investors and fund managers to track and invest in this specific market capitalization tier.

Overview

The index is designed to provide a transparent and representative barometer for mid-cap equities, which are typically defined as companies with market capitalizations between approximately $3.6 billion and $13.1 billion, though these thresholds are fluid. Managed by S&P Dow Jones Indices, a joint venture majority-owned by S&P Global, the index forms part of the core U.S. equity suite alongside the S&P 500 and the S&P 600. Constituents are drawn from major U.S. exchanges including the New York Stock Exchange and Nasdaq, covering a diverse range of GICS sectors such as Industrials, Financials, and Information Technology. Its methodology emphasizes liquidity and financial viability, ensuring it represents established, yet still-growing, public companies.

History

The index was launched by Standard & Poor's in June 1991 to fill a perceived gap in U.S. market coverage between the large-cap S&P 500 and the then small-cap S&P SmallCap 600. Its creation responded to growing investor interest in the performance dynamics of medium-sized companies, which often exhibit different growth and volatility characteristics than their larger counterparts. Over the decades, it has undergone periodic reconstitutions and rebalances to maintain its representative nature, reflecting broader economic shifts like the dot-com bubble and the Financial crisis of 2007–2008. The administration of the index moved to the joint venture S&P Dow Jones Indices following its formation in 2012, integrating it with other flagship indices like the Dow Jones Industrial Average.

Composition and Methodology

Eligibility for inclusion requires that a company be a U.S. corporation, trade on a major exchange like the NYSE Arca, and meet specific size, liquidity, and financial viability criteria set by S&P Dow Jones Indices. The index is float-adjusted market-capitalization weighted, meaning the influence of each constituent is proportional to its publicly available shares, preventing undue dominance by any single company. Sector representation aims to mirror the broader mid-cap universe, with regular reviews conducted by the S&P Index Committee to add or remove stocks through events like quarterly rebalances. This committee also ensures companies do not become too large, typically moving them to the S&P 500 if they exceed size thresholds, maintaining the index's pure mid-cap exposure.

Performance

Historically, the index has demonstrated a risk/return profile distinct from both the Russell 2000 and the S&P 500, often offering higher growth potential than large-caps with less volatility than some small-cap indices. Its performance is closely tracked by financial media such as Bloomberg L.P. and The Wall Street Journal, and it has been the basis for numerous investment products, including exchange-traded funds like the iShares Core S&P Mid-Cap ETF and futures contracts on the Chicago Mercantile Exchange. Long-term returns have been influenced by economic cycles, with notable periods of outperformance during expansions when mid-cap companies benefit from operational agility and domestic market focus.

Use in Investing

The index is a foundational tool for passive investment strategies, serving as the underlying benchmark for a vast ecosystem of financial products. Major asset managers like BlackRock and State Street Corporation offer index funds and ETFs that replicate its holdings, providing investors with efficient exposure to the mid-cap segment. Active managers also use it as a performance benchmark for mid-cap focused mutual funds and separate accounts. Furthermore, derivatives such as options and futures linked to the index are traded on venues like the Cboe Global Markets, allowing for sophisticated hedging and speculative strategies by institutions and hedge funds like Bridgewater Associates.

Comparison with Other Indices

The index is most directly compared to the Russell Midcap Index and the Dow Jones U.S. Mid-Cap Total Stock Market Index, though its methodology involving committee selection differs from the purely rules-based approach of the Russell Indexes. It generally contains larger and more liquid companies than the S&P 600, while excluding the mega-cap firms dominant in the NASDAQ-100. Compared to the MSCI USA Mid Cap Index, it has a stricter focus on U.S. domicile and financial health requirements. This curated approach aims to provide a more investable and stable representation of the mid-cap market than broader, all-encompassing indices.

Category:Stock market indices in the United States Category:S&P Dow Jones Indices