While the proven Zacks Rank places an emphasis on earnings estimates and estimate revisions to find strong stocks, we also know that investors tend to develop their own individual strategies. With this in mind, we are always looking at value, growth, and momentum trends to discover great companies.Of these, perhaps no stock market trend is more popular than value investing, which is a strategy that has proven to be successful in all sorts of market environments. Value investors rely on traditional forms of analysis on key valuation metrics to find stocks that they believe are undervalued, leaving room for profits.Luckily, Zacks has developed its own Style Scores system in an effort to find stocks with specific traits. Value investors will be interested in the system's "Value" category. Stocks with both "A" grades in the Value category and high Zacks Ranks are among the strongest value stocks on the market right now.One stock to keep an eye on is Financial Institutions (FISI). FISI is currently holding a Zacks Rank of #1 (Strong Buy) and a Value grade of A. The stock is trading with a P/E ratio of 8.15, which compares to its industry's average of 9.73. Over the last 12 months, FISI's Forward P/E has been as high as 14.41 and as low as 5.16, with a median of 8.08.Another notable valuation metric for FISI is its P/B ratio of 0.80. The P/B ratio pits a stock's market value against its book value, which is defined as total assets minus total liabilities. This stock's P/B looks solid versus its industry's average P/B of 0.92. Over the past 12 months, FISI's P/B has been as high as 1.28 and as low as 0.53, with a median of 0.66.Value investors also frequently use the P/S ratio. This metric is found by dividing a stock's price with the company's revenue. This is a prefered metric because revenue can't really be manipulated, so sales are often a truer performance indicator. FISI has a P/S ratio of 1.73. This compares to its industry's average P/S of 2.31.Finally, investors will want to recognize that FISI has a P/CF ratio of 7.27. This figure highlights a company's operating cash flow and can be used to find firms that are undervalued when considering their impressive cash outlook. FISI's P/CF compares to its industry's average P/CF of 11.35. FISI's P/CF has been as high as 9.62 and as low as 3.88, with a median of 5.69, all within the past year.These figures are just a handful of the metrics value investors tend to look at, but they help show that Financial Institutions is likely being undervalued right now. Considering this, as well as the strength of its earnings outlook, FISI feels like a great value stock at the moment.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Financial Institutions, Inc. (FISI): Free Stock Analysis Report To read this article on Zacks.com click here.