Conceptually, investors are thought be more risk-tolerant at younger ages and more risk-averse as they age. In fact, this idea is built into many asset allocation strategies and provides the structure for target-date mutual funds. But is it still valid?

Significant progress on a major sticking point in the NFL labor impasse — soaring rookie salaries — during marathon talks Thursday raised hopes that a tentative agreement in principle could perhaps come within 24 hours, according to two people familiar with the negotiations.

Two weeks after they filed a complaint over their lack of involvement in the labor talks between the NFL and players, and as those talks appear to be gaining traction toward a new collective bargaining agreement, a group of retired football players sent the league a letter asking to be...