Is it 1999 again? Because Microsoft (MSFT) appears to be crushing it.

Microsoft's stock is up more than 25% since the beginning of this year, having avoided most of the recent declines afflicting the FAANG stocks. And it's even surpassed Apple (AAPL) and Amazon (AMZN)  again as the most valuable public company in the world, with a market cap of roughly $840 billion as of Wednesday afternoon, compared to $818 billion for Amazon and $804 billion for Apple (after many years of leadership by Apple, the trio have been trading off the lead in recent months). 

But as TheStreet's Eric Jhonsa noted recently, Microsoft's turnaround has been a long time in the making. The software giant's upswing dates back to at least 2014, when CEO Satya Nadella took the reins at the legacy tech giant and prioritized strategic M&A, such as Microsoft's $26 billion purchase of LinkedIn in 2016, and investments in public cloud services and apps. Shortly after taking over as CEO, Nadella redefined Microsoft in a memo to employees as "the productivity and platform company for the mobile-first and cloud-first world."

At a recent BI Ignition event, NYU professor Scott Galloway cited the diversity of Microsoft's revenue streams, as well as the continued "monogamy" between Microsoft's customers and its products as factors in the software giant's resurgence.

"The ultimate monogamous relationship over the last 30 years has been the relationship between corporate America and this recurring revenue stream called Microsoft Office," Galloway said. "The market loves that."

Jeff Marks, an analyst with Jim Cramer's Action Alerts Plus portfolio, which owns Microsoft, noted similarly that "the investment case for Microsoft has strengthened in recent years due to its durable growth in Commercial Office 365 and the secular trends in the cloud, where Azure has been a dominant player in the hybrid space." 

Microsoft's revenue breakdown is split relatively evenly among three segments: Intelligent Cloud services, which includes Azure; productivity services that include enterprise and consumer products like Office365; and personal computing, which encompasses Windows as well as Microsoft's Xbox and gaming services.

Investors are reaping the benefits of Microsoft's investments in cloud services, with Microsoft's Azure having gradually gained ground on Amazon Web Services. As of a recent report from Cloud Security Alliance, Azure grew its share of the public cloud market to 29.4% versus AWS's 41.5% share of the market. And in its October earnings report, Microsoft reported that Azure revenues grew 76% year over year.

Gaming is another bright spot. As of its last earnings, Microsoft's gaming revenue rose 44% year over year to $2.73 billion -- and executives expect that could grow further. 

"The great thing about gaming today is all forms of monetization are actually growing and are very healthy," said Phil Spencer, Microsoft's head of gaming, at a Barclay's investor conference last week. "It is an activity that the youth on the planet love. It is what they're engaging in...And I think there's a real monetization capability there that we haven't even tapped yet."

Bullish analysts are predicting that the combination of Microsoft's cloud momentum and its entrenched consumer and enterprise products such as Office 365, could bear even more fruit for investors into next year. 

"We are bullish on Microsoft into 2019 given our thesis that Azure's cloud momentum is still in its early days of playing out with the company's massive installed base," wrote Wedbush's Dan Ives. "This combination of dynamics should enable Nadella to further transform Microsoft into a cloud behemoth over the coming years and translate to further earnings and multiple expansion in 2019."

Microsoft, Amazon and Apple are holdings in Jim Cramer's Action Alerts PLUS member club. Want to be alerted before Jim Cramer buys or sells these stocks? Learn more now.