The proven Zacks Rank system focuses on earnings estimates and estimate revisions to find winning stocks. Nevertheless, we know that our readers all have their own perspectives, so we are always looking at the latest trends in value, growth, and momentum to find strong picks.Of these, value investing is easily one of the most popular ways to find great stocks in any market environment. Value investors use tried-and-true metrics and fundamental analysis to find companies that they believe are undervalued at their current share price levels.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.Posco (PKX) is a stock many investors are watching right now. PKX is currently sporting a Zacks Rank of #2 (Buy), as well as a Value grade of A.Value investors also frequently use the P/S ratio. This metric is found by dividing a stock's price with the company's revenue. Some people prefer this metric because sales are harder to manipulate on an income statement. This means it could be a truer performance indicator. PKX has a P/S ratio of 0.48. This compares to its industry's average P/S of 0.54.Finally, investors will want to recognize that PKX has a P/CF ratio of 3.71. This metric focuses on a firm's operating cash flow and is often used to find stocks that are undervalued based on the strength of their cash outlook. This company's current P/CF looks solid when compared to its industry's average P/CF of 11.63. Over the past 52 weeks, PKX's P/CF has been as high as 5.64 and as low as 3.25, with a median of 4.55.These are just a handful of the figures considered in Posco's great Value grade. Still, they help show that the stock is likely being undervalued at the moment. Add this to the strength of its earnings outlook, and we can clearly see that PKX is an impressive value stock right now. Zacks’ Top Picks to Cash in on Artificial Intelligence This world-changing technology is projected to generate $100S of billions by 2025. From self-driving cars to consumer data analysis, people are relying on machines more than we ever have before. Now is the time to capitalize on the 4th Industrial Revolution. Zacks’ urgent special report reveals 6 AI picks investors need to know about today.See 6 Artificial Intelligence Stocks With Extreme Upside Potential>>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 POSCO (PKX): Get Free Report To read this article on Zacks.com click here.