A Random Walk Down Wall Street: The Time-Tested Strategy for Successful Investing

by Burton G. Malkiel

The core of every portfolio should consist of low-cost, tax-efficient, broad-based index funds.

If you do want to take a chance that some risk factors will generate improved risk-adjusted returns in the future, you can do so most prudently if the core of your portfolio consists of capitalization-weighted broad-based index funds.