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.

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 tried-and-true metrics and fundamental analysis to find companies that they believe are undervalued at their current share price levels.

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.

One stock to keep an eye on is Allegiant (ALGT). ALGT is currently sporting a Zacks Rank of #1 (Strong Buy), as well as a Value grade of A. The stock has a Forward P/E ratio of 9.32. This compares to its industry's average Forward P/E of 16. Over the past year, ALGT's Forward P/E has been as high as 61.81 and as low as 7.88, with a median of 10.34.

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. ALGT has a P/S ratio of 0.54. This compares to its industry's average P/S of 0.56.

Frontier Group (ULCC) may be another strong Transportation - Airline stock to add to your shortlist. ULCC is a # 2 (Buy) stock with a Value grade of A.

Frontier Group is currently trading with a Forward P/E ratio of 8.33 while its PEG ratio sits at 0.23. Both of the company's metrics compare favorably to its industry's average P/E of 16 and average PEG ratio of 0.89.

ULCC's price-to-earnings ratio has been as high as 148.72 and as low as 4.55, with a median of 11.60, while its PEG ratio has been as high as 0.25 and as low as 0.21, with a median of 0.22, all within the past year.

Additionally, Frontier Group has a P/B ratio of 2.76 while its industry's price-to-book ratio sits at 4.99. For ULCC, this valuation metric has been as high as 3.75, as low as 1.22, with a median of 2.64 over the past year.

Value investors will likely look at more than just these metrics, but the above data helps show that Allegiant and Frontier Group are likely undervalued currently. And when considering the strength of its earnings outlook, ALGT and ULCC sticks out as one of the market's strongest value stocks.

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Allegiant Travel Company (ALGT) : Free Stock Analysis Report

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This article originally published on Zacks Investment Research (zacks.com).

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