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.

Considering these trends, value investing is clearly one of the most preferred ways to find strong stocks in any type of market. Value investors use fundamental analysis and traditional valuation metrics to find stocks that they believe are being undervalued by the market at large.

Zacks has developed the innovative Style Scores system to highlight stocks with specific traits. For example, value investors will be interested in stocks with great grades in the "Value" category. When paired with a high Zacks Rank, "A" grades in the Value category are among the strongest value stocks on the market today.

One stock to keep an eye on is NN Group (NNGRY). NNGRY is currently holding a Zacks Rank of #2 (Buy) and a Value grade of A. The stock has a Forward P/E ratio of 5.13. This compares to its industry's average Forward P/E of 7.27. Over the last 12 months, NNGRY's Forward P/E has been as high as 9.33 and as low as 4.20, with a median of 7.91.

Investors should also note that NNGRY holds a PEG ratio of 0.40. This popular figure is similar to the widely-used P/E ratio, but the PEG ratio also considers a company's expected EPS growth rate. NNGRY's PEG compares to its industry's average PEG of 0.69. Over the past 52 weeks, NNGRY's PEG has been as high as 4.67 and as low as 0.22, with a median of 0.37.

Investors should also recognize that NNGRY has a P/B ratio of 0.60. 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. This stock's P/B looks solid versus its industry's average P/B of 1.72. NNGRY's P/B has been as high as 0.70 and as low as 0.45, with a median of 0.56, over the past year.

Another great Insurance - Life Insurance stock you could consider is Reinsurance Group of America (RGA), which is a # 1 (Strong Buy) stock with a Value Score of A.

Furthermore, Reinsurance Group of America holds a P/B ratio of 1.36 and its industry's price-to-book ratio is 1.72. RGA's P/B has been as high as 2.40, as low as 1.14, with a median of 1.24 over the past 12 months.

These are only a few of the key metrics included in NN Group and Reinsurance Group of America strong Value grade, but they help show that the stocks are likely undervalued right now. When factoring in the strength of its earnings outlook, NNGRY and RGA look like an impressive value stock at the moment.