Here at Zacks, our focus is on the proven Zacks Rank system, which emphasizes earnings estimates and estimate revisions to find great stocks. Nevertheless, we are always paying attention to the latest value, growth, and momentum trends to underscore strong picks.

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 stock to keep an eye on is NN Group (NNGRY Quick QuoteNNGRY - Free Report) . NNGRY is currently holding a Zacks Rank of #2 (Buy) and a Value grade of A.

We also note that NNGRY holds a PEG ratio of 0.27. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. NNGRY's PEG compares to its industry's average PEG of 0.63. Within the past year, NNGRY's PEG has been as high as 5.13 and as low as 0.27, with a median of 4.14.

Another valuation metric that we should highlight is NNGRY's P/B ratio of 0.56. 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 1.58. Over the past year, NNGRY's P/B has been as high as 0.70 and as low as 0.50, with a median of 0.56.

These figures are just a handful of the metrics value investors tend to look at, but they help show that NN Group is likely being undervalued right now. Considering this, as well as the strength of its earnings outlook, NNGRY feels like a great value stock at the moment.