Investors interested in stocks from the Financial - Investment Bank sector have probably already heard of JMP (JMP) and Tradeweb Markets (TW). 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.There are plenty of strategies for discovering value stocks, but we have found that pairing a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system produces the best returns. The proven Zacks Rank puts an emphasis on earnings estimates and estimate revisions, while our Style Scores work to identify stocks with specific traits.JMP has a Zacks Rank of #2 (Buy), while Tradeweb Markets has a Zacks Rank of #3 (Hold) right now. This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that JMP is likely seeing its earnings outlook improve to a greater extent. But this is just one factor that value investors are interested in.Value investors are also interested in a number of tried-and-true valuation metrics that help show when a company is undervalued at its 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.JMP currently has a forward P/E ratio of 14.55, while TW has a forward P/E of 53.72. We also note that JMP has a PEG ratio of 1.45. 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. TW currently has a PEG ratio of 5.11.Another notable valuation metric for JMP is its P/B ratio of 2.02. The P/B ratio is used to compare a stock's market value with its book value, which is defined as total assets minus total liabilities. For comparison, TW has a P/B of 3.51.Based on these metrics and many more, JMP holds a Value grade of B, while TW has a Value grade of F.JMP sticks out from TW in both our Zacks Rank and Style Scores models, so value investors will likely feel that JMP is the better option right now.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 JMP Group LLC (JMP): Free Stock Analysis Report Tradeweb Markets Inc. (TW): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research