Question: There are three ways of constructing an index. Which type of index offers the best potential for individual investor ?
Answer: Let us first define the three ways of constructing an index:
1. Price-Weighted Index e.g. Dow Jones Industrial Average
Stock A = $2. Accounts for 20% of the index
Stock B = $8. Accounts for 80% of the index
2. Equally-Weighted Index e.g. many ETFs
Stock A = $2. Accounts for 50% of the index
Stock B = $8. Accounts for 50% of the index
3. Capitalization-Weighted Index e.g. S&P 500
Stock A = $2; shares outstanding = 50; market capitalization = 2 * 50 = 100.
Stock B = $8, shares outstanding = 5; market capitalization = 8 * 5 = 40.
Therefore,
Stock A accounts for 100 / 140 = 71% of the index
Stock B accounts for 40 / 140 = 29% of the index
What does it mean to you?
In a long-run, small capitalization stock indexes tend to outperform the general market. Therefore investors should hold more Equally-Weighted Indexes as they give a greater weight to small caps. At the same time, buying a broadly diversified index protects from the risk of holding an individual company.