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 use a variety of methods, including tried-and-true valuation metrics, to find these stocks.

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 company value investors might notice is Omnicom Group (OMC Quick QuoteOMC - Free Report) . OMC is currently sporting a Zacks Rank of #2 (Buy) and an A for Value.

We should also highlight that OMC has a P/B ratio of 4.52. 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. This company's current P/B looks solid when compared to its industry's average P/B of 6.24. Over the past 12 months, OMC's P/B has been as high as 4.84 and as low as 3.92, with a median of 4.35.

Finally, we should also recognize that OMC has a P/CF ratio of 12.23. This metric takes into account a company's operating cash flow and can be used to find stocks that are undervalued based on their solid cash outlook. OMC's P/CF compares to its industry's average P/CF of 13.55. Over the past 52 weeks, OMC's P/CF has been as high as 12.32 and as low as 9.29, with a median of 10.99.

Value investors will likely look at more than just these metrics, but the above data helps show that Omnicom Group is likely undervalued currently. And when considering the strength of its earnings outlook, OMC sticks out at as one of the market's strongest value stocks.