Have the FAANGs gone their separate ways for good?

The stocks share one important thing in common: Huge gains in recent years that have outperformed the broader market by a wide margin. But their differences now dwarf their similarities in the eyes of many professional investors and portfolio managers.

The past few months haven't been kind to tech stocks, relatively speaking. Netflix's (NFLX) - Get ReportJuly subscriber miss sent the stock into a nosedive from which it hasn't fully recovered. Amazon's (AMZN) - Get Report stock has sagged after its third quarter earnings revealed a tepid holiday outlook. Apple (AAPL) - Get Report investors weren't pleased with its recent decision to stop releasing iPhone unit sales amid a mixed third quarter earnings report. And Facebook (FB) - Get Report , of course, is dealing with its own host of demons including election interference, data breaches and harmful content.

All of that, amidst heightened market volatility, has investors spooked -- and taking a microscope to the FAANG stocks' unique issues.

"Investors have gotten to a point that they're a bit jittery, and they are looking at every company from every angle -- like they should all the time, frankly," said Chris Cook of Beacon Capital Management, an Ohio-based investment advisory firm that manages upwards of $2.5 billion in assets.

The FAANG's outsized market caps, combined with financial products like ETFs that trade them together, have created a tendency to rise and fall as a pack. But as the FAANG's extended hyper-growth streak appears to fall apart, investors are debating the stocks' individual merits and making their own revisions to the famous acronym.

"Microsoft now fits better into the FANG group than Netflix," said investment strategist Lyn Alden, making note of Netflix's negative free cash flow and significantly smaller valuation than the rest of the group. "Microsoft (MSFT) - Get Report is highly profitable and has a market capitalization in line with Alphabet and Amazon. They're doing amazing and are a much better representation of technology and growth in the U.S. economy than Netflix."

Meanwhile, Danielle Shay Gum of Simpler Trading is more bullish on 'MAAG' as the next source of growth in the tech sector: "I think 'FANG' should consist of Microsoft, Adobe (ADBE) - Get Report , Apple and possibly Google, but certainly Netflix and Facebook no longer fit the bill," she said, citing Facebook's inability to shake bad news and Netflix's unprofitability as reasons why they're now the odd men out.

Certainly there's no consensus on where the next bull run in tech might come from. But mature tech companies -- such as Facebook, Alphabet (GOOGL) - Get Report and Amazon, which are around 15, 20 and 25 years old now, respectively -- shouldn't be lumped together in the eyes of investors just because they're valuable tech businesses. That time has long since passed according to Barbara Browning, who manages large cap funds at Pax World Funds.

"There was a period of time when [FAANGs] were in their infancy, and they had the commonality of being internet businesses, but now I don't think it's appropriate to trade them together," she said. "Because they all have their own business models, they are going to start being assigned different valuations by investors and that, over time, will lead de facto to being traded differently as well."

Beacon's Cook stressed the virtues of diversifying one's portfolio across sectors, rather than focusing too much on a small group of large-cap stocks: "It works great on the upside, but it hurts on the way down as well," he said. 

Whether you're inclined to bet on FAMG, MAAG or something else entirely, it's clear that at least for now, the FAANGs aren't exactly what they used to be. 

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