A Yale professor has developed a new investment formula that challenges conventional wisdom about portfolio allocation. The approach suggests investors need more stocks than traditional models recommend, regardless of whether they're young, middle-aged, or retired.

The formula takes a fresh look at key factors including age, income, and risk tolerance. Unlike traditional models that typically reduce stock exposure as investors age, this new approach argues for maintaining higher equity allocations throughout an investor's lifecycle.

This shift could have significant implications for how millions of investors structure their retirement portfolios. Financial advisors and individual investors alike may need to reconsider their asset allocation strategies if the formula gains widespread acceptance in the investment community.