Morningstar Chief U.S. Markets Strategist David Sekera believes the massive sell-off in Big Tech this year could now be overdone. The broader tech sector has borne the brunt of a market rotation out of growth stocks and into value names this year, as monetary tightening became more apparent. The Nasdaq Composite is down 28% year-to-date, putting the tech-heavy index firmly in bear market territory. FAANG stocks, too, are trading at deep discounts, Sekera told CNBC Pro Talks on Wednesday. One FAANG stock in particular — Meta — has become so cheap, investors can buy it at a large "margin of safety," he said. Identifying a "margin of safety" is a classic value investing strategy — and one of Warren Buffett 's cornerstone principles — that looks for stocks with an intrinsic value that is well above their market valuation. Value-focused investors like Buffett believe it is a key factor to consider when assessing the risk and return potential of a company, particularly during periods of extreme market volatility. And it has led Sekera to argue that now could be the time to look at FAANG stocks once again. 'Margin of safety' stock Sekera noted that both Alphabet and Facebook-parent Meta are trading at "very deep discounts" to their long-term valuations. He estimated that Alphabet is trading at a 35% discount to Morningstar's fair value on the stock, while Meta trades at under half of its fair value. Alphabet's stock is down more than 20% this year, and trades at a P/E ratio of 18.3x. Meanwhile, more than half of Meta's market capitalization has been wiped out this year, and the stock is now trading at a price-to earnings ratio of just 12.6x — the lowest among its peers, according to FactSet data. Around 80% of analysts covering the stock give it a buy rating. "It's always hard to know exactly when the market will catch back up to where we think that intrinsic valuation is … But at this point, you know, we think you can buy that stock at such a large margin of safety — investors would be well positioned in that name," Sekera said of Meta. He said the company is set to benefit from the long-term structural growth in digital advertising — despite some negative publicity this year. Meta said in February that Apple's App Tracking Transparency feature, which reduces targeting capabilities by limiting advertisers from accessing an iPhone user identifier, will hit the social media company's sales this year by about $10 billion . But Meta has since stepped up its efforts in response to those headwinds, moving to generate more revenue from Instagram Reels and investing in artificial intelligence to drive content recommendations the way its competitor — ByteDance-owned TikTok — does.