Indexes and Sectors

What you will learn

• Understand what a stock market index is and meet the major ones.
• Learn what market sectors are and how they group companies.
• See how reading indexes and sectors together gives you the real story of the market.

Core concepts

When you hear on the news that "the market is up today," they are usually talking about an Index. An index is simply a tracked basket of stocks used to measure how a specific part of the market is performing. Instead of checking thousands of individual stock prices, you can look at one index to get the general mood.

The most famous indexes in the US are:

• The S&P 500: Tracks 500 of the largest US companies. It is the most common benchmark for the overall US stock market.
• The Nasdaq 100: Tracks 100 of the largest non-financial companies on the Nasdaq exchange. It is heavily focused on technology and growth companies.
• The Dow Jones Industrial Average (The Dow): Tracks just 30 large companies. It is famous because it is old, but it is too small to be a great measure of the whole market.
• The Russell 2000: Tracks 2,000 smaller US companies (small-caps).

While indexes group companies by size or exchange, Sectors group them by what they actually do. The US stock market uses a strict standard (called GICS) that divides all public companies into exactly 11 sectors:

• Information Technology (Software, hardware, semiconductors)
• Health Care (Hospitals, pharmaceuticals, biotech)
• Financials (Banks, insurance, credit cards)
• Consumer Discretionary (Things people want: cars, luxury goods, travel)
• Consumer Staples (Things people need: groceries, toothpaste, household goods)
• Communication Services (Internet providers, media, entertainment)
• Industrials (Airlines, railroads, machinery, defense)
• Energy (Oil, gas, consumable fuels)
• Utilities (Electricity, water, gas providers)
• Real Estate (Property developers, real estate investment trusts)
• Materials (Mining, chemicals, forestry)

How to read them together

Indexes tell you which basket is moving, while sectors tell you why the basket is moving.

For example, if the S&P 500 is up slightly, but the Nasdaq 100 is up a lot, it usually means Technology companies are having a great day. If the Russell 2000 is falling while the S&P 500 is rising, it might mean investors are nervous and prefer the safety of giant companies over smaller, riskier ones.

Sectors also behave differently depending on what is happening in the world. When the economy is booming, "cyclical" sectors like Technology and Consumer Discretionary (luxury goods, travel) tend to do well. When people are worried about a recession, they often hide in "defensive" sectors like Healthcare or Consumer Staples, because people still need medicine and toothpaste even in a bad economy.

By understanding indexes and sectors, you stop seeing the stock market as one giant blob. You start seeing it as a collection of different neighborhoods, each reacting to news in its own way.

Common mistakes

• Assuming "the market is up" means every single stock or sector is doing well.
• Using the Dow Jones (only 30 stocks) as your only gauge of market health.
• Forgetting that a broad index like the S&P 500 can be heavily influenced by just a few massive technology companies.