Market Vertical · U.S. Large-Cap Index
The S&P 500
The S&P 500 is a market-cap-weighted index of 500 large U.S. companies across every major sector. It's the most referenced benchmark for the U.S. stock market. When people say "the market was up today," they're usually talking about the S&P 500. It's not every stock — it's 500 companies chosen by a committee based on size, liquidity, and profitability.
What it covers
The index spans 11 sectors: Technology, Healthcare, Financials, Consumer Discretionary, Communication Services, Industrials, Consumer Staples, Energy, Utilities, Real Estate, and Materials. Because it's market-cap weighted, the largest companies have the most influence. The Magnificent Seven — Apple, Microsoft, Nvidia, Alphabet, Amazon, Meta, and Tesla — account for roughly 30% of the index's total movement. GenHedge tracks each Mag 7 name individually within this vertical and surfaces the top mover, driver, and context in every issue.
What moves it
Earnings season (when companies report quarterly results) is the biggest recurring driver. Beyond that: Fed policy and interest rates, inflation data (CPI and PCE reports), jobs reports, and geopolitical events. Sector rotation also matters — when investors shift money between sectors, the index composition determines how that affects the total.
Key terms
Index
A basket of securities designed to represent a market or segment. You can't buy "the index" directly — you buy funds that track it (like SPY or VOO).
Market-Cap Weighted
Bigger companies have more influence on the index. A 1% move in Apple affects the S&P 500 more than a 1% move in a small company.
Sector Rotation
Money moving from one industry group to another. Common when macro conditions change — like rotating from growth stocks to defensive stocks when rates rise.
Earnings Season
Four times a year, public companies report revenue, profit, and forward guidance. Markets price in expectations before reports and react to surprises.
In the newsletter
In the newsletter, the S&P 500 signal covers index-level moves, the sector driving them, and the Mag 7 names leading or lagging the index. You get the "why" behind a green or red day — not a prediction of what happens next.
Sub-verticals
S&P 500 is in every issue.
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