Here at Zacks, we focus on our proven ranking system, which places an emphasis on earnings estimates and estimate revisions, to find winning stocks. But we also understand that investors develop their own strategies, so we are constantly looking at the latest trends in value, growth, and momentum to find strong companies for our readers.

Looking at the history of these trends, perhaps none is more beloved than value investing. This strategy simply looks to identify companies that are being undervalued by the broader market. Value investors use a variety of methods, including tried-and-true valuation metrics, to find these stocks.

In addition to the Zacks Rank, investors looking for stocks with specific traits can utilize our Style Scores system. Of course, value investors will be most interested in the system's "Value" category. Stocks with "A" grades for Value and high Zacks Ranks are among the best value stocks available at any given moment.

Air China (AIRYY) is a stock many investors are watching right now. AIRYY is currently holding a Zacks Rank of #2 (Buy) and a Value grade of A.

We should also highlight that AIRYY has a P/B ratio of 1.71. 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. AIRYY's current P/B looks attractive when compared to its industry's average P/B of 4.66. Over the past 12 months, AIRYY's P/B has been as high as 1.93 and as low as 1.25, with a median of 1.57.

Value investors also frequently use the P/S ratio. This metric is found by dividing a stock's price with the company's revenue. This is a popular metric because sales are harder to manipulate on an income statement, so they are often considered a better performance indicator. AIRYY has a P/S ratio of 0.45. This compares to its industry's average P/S of 0.6.

If you're looking for another solid Transportation - Airline value stock, take a look at United Airlines (UAL). UAL is a # 2 (Buy) stock with a Value score of A.

Shares of United Airlines currently holds a Forward P/E ratio of 9.28, and its PEG ratio is 1.03. In comparison, its industry sports average P/E and PEG ratios of 16.09 and 0.81.

UAL's Forward P/E has been as high as 9.45 and as low as 3.63, with a median of 4.66. During the same time period, its PEG ratio has been as high as 1.13, as low as 0.08, with a median of 0.59.

United Airlines also has a P/B ratio of 2.74 compared to its industry's price-to-book ratio of 4.66. Over the past year, its P/B ratio has been as high as 2.95, as low as 1.18, with a median of 1.64.

These are just a handful of the figures considered in Air China and United Airlines's great Value grade. Still, they help show that the stock is likely being undervalued at the moment. Add this to the strength of its earnings outlook, and we can clearly see that AIRYY and UAL is an impressive value stock right now.

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