Benjamin Graham defined stocks trading with a large margin of safety as those whose prices were below net working capital after all debt was deducted. Graham found that a portfolio of such bargain issues outperformed the broader indexes, with none of the 150 identified stocks incurring significant losses. An updated version of Graham’s Deep Value screen was created in 2012; through November 2016, the portfolio beat the S&P 500 with all its stocks achieving positive returns.
Johnson, Robert R. PhD; Robinson, Thomas R. PhD; and Horan, Stephen M. PhD, "Deep Value Investing Has Not Gone Out of Style" (2017). Faculty Publications. 678.