The article explores why many people don't invest in risky assets, even when they could make more money. By using a utility function with a kink at a certain wealth level, the researchers found that investors may choose not to invest in risky assets within a specific range of expected returns. This range is determined by comparing stock returns to preference parameters. However, if the wealth level is different, investors will invest in risky assets whenever they can make more money than with a riskless asset.