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, value investing is easily one of the most popular ways to find great stocks in any market environment. Value investors use a variety of methods, including tried-and-true valuation metrics, to find these stocks.

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 company to watch right now is Humana (HUM Quick QuoteHUM - Free Report) . HUM is currently sporting a Zacks Rank #2 (Buy), as well as an A grade for Value.

We should also highlight that HUM has a P/B ratio of 1.66. The P/B is a method of comparing a stock's market value to 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 2.25. HUM's P/B has been as high as 2.30 and as low as 1.45, with a median of 1.82, over the past year.

Value investors also love the P/S ratio, which is calculated by simply dividing a stock's price with the company's sales. This is a preferred metric because revenue can't really be manipulated, so sales are often a truer performance indicator. HUM has a P/S ratio of 0.25. This compares to its industry's average P/S of 0.28.

These are only a few of the key metrics included in Humana's strong Value grade, but they help show that the stock is likely undervalued right now. When factoring in the strength of its earnings outlook, HUM looks like an impressive value stock at the moment.