Investors interested in stocks from the Financial - Investment Management sector have probably already heard of Principal Financial (PFG) and T. Rowe Price (TROW). But which of these two stocks offers value investors a better bang for their buck right now? We'll need to take a closer look.The best way to find great value stocks is to pair a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Currently, both Principal Financial and T. Rowe Price are holding a Zacks Rank of # 2 (Buy). This means that both companies have witnessed positive earnings estimate revisions, so investors should feel comfortable knowing that both of these stocks have an improving earnings outlook. But this is just one piece of the puzzle for value investors.Value investors analyze a variety of traditional, tried-and-true metrics to help find companies that they believe are undervalued at their current share price levels.The Style Score Value grade factors in a variety of key fundamental metrics, including the popular P/E ratio, P/S ratio, earnings yield, cash flow per share, and a number of other key stats that are commonly used by value investors.PFG currently has a forward P/E ratio of 10.19, while TROW has a forward P/E of 16.53. We also note that PFG has a PEG ratio of 0.67. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. TROW currently has a PEG ratio of 1.84.Another notable valuation metric for PFG is its P/B ratio of 1.09. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. By comparison, TROW has a P/B of 6.12.These are just a few of the metrics contributing to PFG's Value grade of A and TROW's Value grade of D.Both PFG and TROW are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that PFG is the superior value option 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 Principal Financial Group, Inc. (PFG): Free Stock Analysis Report T. Rowe Price Group, Inc. (TROW): Free Stock Analysis Report To read this article on Zacks.com click here.