David Swensen was hardly a household name. Yet he was a legend among professional investors. Swensen ran Yale University's endowment since 1985 and he earned an average annual return of more than 13%. He died May 5 from cancer at age 67.

Swensen was an investment pioneer. When he started at Yale, the typical college and university fund put the bulk of its money into stocks and bonds, often starting with the classic 60/40 mix. He instead committed substantial sums to a well-diversified basket of longer-term alternative investments, including private equity, foreign stocks, timber, real estate, venture capital and inflation-protected securities. His approach greatly influenced the way endowments and foundations managed their money and his 2000 book "Pioneering Portfolio Management" is required reading for those in the business.

Less well-known is that Swensen wrote a 2005 book targeted at individual investors, "Unconventional Success: A Fundamental Approach to Personal Investment." He advocated that individual investors steer clear of the approach he developed for Yale's endowment. Individuals don't have the time horizons or access to the kind of information necessary to make that approach work. Swensen also poured scorn on the standard advice by the for-profit mutual fund industry that individuals fare best when they turn over their money to professional money managers.

Forget trying to beat the market, he wrote. Swenson called for individual investors to embrace widespread diversification, invest with an equity orientation for the long-haul through market-mimicking index funds, and maintain a tight focus on keeping fees low.

There's nothing remarkable about that advice these days, although with the current Robinhood-inspired day trading and crypto frenzy I wish more people would pay attention to this sound framework.

Swenson worried that the retirement security of so many American workers was in the hands of actively managed mutual funds through 401(K)s, 403(b)s and other defined contribution savings plans. His insight that workers struggle to save for their retirement while high fees and mediocre money managers erode returns remain too true today. Swensen's bottom line remains: What's good for Wall Street isn't good for Main Street when it comes to workers saving for a secure retirement. That said, until the system changes, his investment framework for individual investors is the best approach for your retirement savings.

Chris Farrell is senior economics contributor for "Marketplace" and Minnesota Public Radio.