An index is a benchmark for reading the market.

To summarize the grades of students in a class, you must decide who to include and what weightings to apply. Stock indices are similar. The price changes of selected stocks are calculated using a set method and used as a benchmark to compare market trends.

The 5,000 points of an index do not mean that one share of stock is worth 5,000 dollars. Each index has different starting criteria and calculation methods, so a higher index number does not mean it is more expensive or superior. Look at the rate of change over the same period and the composition criteria together.

The market you see depends on the name.

The number of companies below represents the typical composition targeted by the index. The actual number of securities and companies may differ due to various stock types or additions and deletions.

S&P 500 provides a broad look at large-cap US stocks.

It includes large-cap U.S. companies from various sectors, but it does not contain all U.S. stocks. Even if the number of companies is large, the influence of each company is not equal. Changes in companies with large float-adjusted market capitalization can have a greater impact on the index.

If a stock with a hypothetical weight of 10% rises by 1%, it contributes approximately 0.1% points, assuming other conditions remain the same. If a stock with a weight of 1% rises by the same 1%, it contributes approximately 0.01% points. Even on days when a few large-cap stocks drive the index up, many other stocks may fall.

Dow 30 uses stock price as the weighting basis.

The official name is the Dow Jones Industrial Average. Even though it has 'Industrial' in its name, it is not an index consisting only of manufacturing companies. Transportation and utilities are handled as separate indices, and it is composed of 30 blue-chip U.S. companies from various sectors.

Because it is price-weighted, a 1% change in a high-priced stock can have a greater impact than the same change in a low-priced stock. The company with the largest total value does not necessarily have the largest weight. Events like stock splits are adjusted in the calculation, so it is insufficient to understand it simply as adding 30 stock prices and dividing by 30.

Read Nasdaq 100, Composite, and Russell 2000 separately as well.

Nasdaq 100 targets large non-financial companies listed on the Nasdaq. While technology companies may have a significant influence, it is not an index that only contains tech stocks. The Nasdaq Composite covers a broader range of listed stocks, so check which index is being referred to when news mentions 'Nasdaq rose'.

Russell 2000 represents the US small-cap sector. The specific market capitalization range and composition criteria observed by Wayf are not identical. Large-cap and small-cap indices may diverge, and an increase in a small-cap index does not necessarily mean the risk of individual small-cap stocks has decreased.

Compare percentages rather than points, and use the same time period.

Hypothetically, an index that rose from 40,000 to 400 points and an index that rose from 5,000 to 50 points are both a 1% increase. A higher number 400 does not necessarily mean a higher rate of increase than 50.

Distinguish between indices that only track price changes and total return indices that reflect dividend reinvestment. If the comparison period, currency, or dividend reflection criteria differ, it is difficult to compare returns directly. Do not assume that futures prices and spot indices are the same number.

An index and the products that track it are different.

The index itself is a calculation benchmark. Products like ETFs that investors actually buy and sell are designed to follow that benchmark. Even if they target the same index, actual results may differ due to costs, tracking differences, market prices, exchange rates, and dividend processing.

Even if you hold both an S&P 500 ETF and a Nasdaq 100 ETF, the same large companies may overlap. An increase in the number of products does not mean they have completely different risks. Check the latest constituent stocks and top weightings. The index name is not a guarantee of safety or returns.

Check what you have read.

• Which group of stocks does the index contain?
• Have you distinguished between market capitalization weighting and price weighting?
• Did you compare based on the same period, currency, and dividend criteria?
• Did you distinguish between the index and the actual product purchased?

Apply what you read to the actual screen

Try it on WAPE

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