An investor, for example, may be interested in purchasing stocks in a particular sector. But if that sector is generally overvalued, it may offer few stocks that are attractively priced. An investor could create a list of all the stocks in that sector that would track various valuation measures, including ratios like trailing price-to-earnings , price-to-sales, and price-to-book, among others. When a company on the list met a specified valuation criterion, such as a PE ratio less than 15, he or she would then know that this stock was a possible candidate for investment. Many investment-oriented websites allow visitors to create watchlists online.