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 rely on traditional forms of analysis on key valuation metrics to find stocks that they believe are undervalued, leaving room for profits.

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 Plains GP Holdings (PAGP Quick QuotePAGP - Free Report) . PAGP is currently holding a Zacks Rank of #1 (Strong Buy) and a Value grade of A. The stock holds a P/E ratio of 11.56, while its industry has an average P/E of 17.93. Over the past 52 weeks, PAGP's Forward P/E has been as high as 17.04 and as low as 10.12, with a median of 13.98.

Finally, we should also recognize that PAGP has a P/CF ratio of 4.05. 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. PAGP's current P/CF looks attractive when compared to its industry's average P/CF of 11.61. Over the past year, PAGP's P/CF has been as high as 4.74 and as low as -35.07, with a median of 3.85.

These are only a few of the key metrics included in Plains GP Holdings'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, PAGP looks like an impressive value stock at the moment.