A value investing strategy is one that builds a portfolio of stocks with high intrinsic value that is not reflected in the stock price when acquired. There are many ways to value stocks and these are usually expressed as a ratio of the current stock price with respect to the measure of value. Common valuation ratios are the P/E or price to earnings ratio, P/S or price to sales ratio, P/NBV or the price to net book value. There are many others. A value strategy will often look for stocks with low valuation ratios with other quantitative parameters that are indicative of upward potential in price appreciation.