S&P 500

The S&P 500 is the single most important equity benchmark in the world. It captures roughly 80% of the total US stock-market capitalisation in a 500-name basket of large-cap companies, and is the benchmark against which trillions of dollars of passive index funds, ETFs, mutual funds and pension allocations are measured. When a global asset allocator says 'US equities', they almost invariably mean the S&P 500. When a financial journalist says 'the market is up 0.4% today', they almost certainly mean the S&P 500.

Unlike the Dow's 30-name committee-picked basket, S&P 500 inclusion is rules-based: a company must be domiciled in the US, have a market cap above a quarterly-updated threshold (around US$ 18 billion in early 2026), demonstrate positive earnings over the trailing year and most recent quarter, have at least 50% of its shares publicly floated, and meet liquidity criteria. The S&P 500 Index Committee at S&P Dow Jones Indices reviews additions and deletions on a rolling basis. The index is float-adjusted and cap-weighted, so larger companies exert proportionally more influence on the index move.

The S&P 500 in its modern form launched on 4 March 1957, replacing the older 90-stock Standard & Poor's Composite Index that had been published since the 1920s. The expansion to 500 names was made possible by the advent of mainframe computing, which allowed daily recalculation of a far larger basket. The index closed at 44.06 on its first day. It crossed 100 in 1968, 500 in 1995, 1,000 in 1998, 2,000 in 2014, 3,000 in 2019, 4,000 in early 2021 and 5,000 in early 2024. The long-run compound annual growth rate including reinvested dividends has averaged roughly 10% per year since inception — the canonical 'US equity-risk premium' figure used in finance textbooks.

Major drawdowns in the index's history: 1973-74 (-48%), the 1987 Black Monday crash (-22.6% in a single day), the 2000-2002 dot-com bust (-49%), the 2007-2009 Global Financial Crisis (-57%), the COVID-19 crash (-34% in 23 trading days in February-March 2020) and the 2022 inflation drawdown (-25%). Each was followed by new all-time highs within 1-5 years.

S&P 500 constituents trade on NYSE and Nasdaq. The index level is continuously calculated during cash hours and via the closely-tracked ES E-mini futures contract overnight. In IST:

Three things to watch when reading the S&P 500 tape. First, sector composition matters: the Information Technology sector now exceeds 30% of the index weight, making the S&P 500 increasingly a 'tech-heavy' rather than 'broad-market' benchmark. Second, the top 10 names (Apple, Microsoft, Nvidia, Amazon, Alphabet, Meta, Berkshire Hathaway, Tesla, Eli Lilly and a rotating tenth) contribute over 30% of total index weight — a phenomenon known as concentration risk. Third, watch the SPX / VIX correlation: a falling SPX with a flat or falling VIX usually signals 'orderly' selling and tends to mean-revert, while a falling SPX with a sharply rising VIX signals fear and extends.

The S&P 500's pre-market 'fair value' is computed from the front-month ES futures contract plus the cost-of-carry basis. Indian traders watching Liveworldmarket overnight see the SPX moving via the ES proxy from 04:30 IST onwards — that's the cleanest macro signal for the eventual Nifty open at 09:15 IST.