Investors looking for stocks in the Business - Services sector might want to consider either BGSF (BGSF) or WNS Holdings Limited (WNS). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.We have found that the best way to discover great value opportunities is to pair a strong Zacks Rank with a great grade in the Value category of our Style Scores system. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Currently, both BGSF and WNS Holdings Limited are holding a Zacks Rank of # 2 (Buy). This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that these stocks have improving earnings outlooks. But this is only part of the picture for value investors.Value investors also tend to look at a number of traditional, tried-and-true figures to help them find stocks that they believe are undervalued at their current share price levels.The Style Score Value grade factors in a variety of key fundamental metrics, including the popular P/E ratio, P/S ratio, earnings yield, cash flow per share, and a number of other key stats that are commonly used by value investors.BGSF currently has a forward P/E ratio of 13.09, while WNS has a forward P/E of 26.71. We also note that BGSF has a PEG ratio of 0.65. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. WNS currently has a PEG ratio of 2.03.Another notable valuation metric for BGSF is its P/B ratio of 2.01. 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. By comparison, WNS has a P/B of 6.42.These metrics, and several others, help BGSF earn a Value grade of A, while WNS has been given a Value grade of D.Both BGSF and WNS are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that BGSF is the superior value option right now. Infrastructure Stock Boom to Sweep America A massive push to rebuild the crumbling U.S. infrastructure will soon be underway. It’s bipartisan, urgent, and inevitable. Trillions will be spent. Fortunes will be made. The only question is “Will you get into the right stocks early when their growth potential is greatest?” Zacks has released a Special Report to help you do just that, and today it’s free. Discover 7 special companies that look to gain the most from construction and repair to roads, bridges, and buildings, plus cargo hauling and energy transformation on an almost unimaginable scale.Download FREE: How to Profit from Trillions on Spending for Infrastructure >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report BGSF, Inc. (BGSF): Free Stock Analysis Report WNS Holdings Limited (WNS): Free Stock Analysis Report To read this article on Zacks.com click here.