Microsoft shares flirted with a 52-week high on Thursday and got pretty close again on Friday, thanks to an upgrade and glowing report from Goldman Sachs analyst Heather Bellini.

The company’s 52-week peak is $61.37 and at one point Friday morning, Microsoft shares hit $61.12 before falling slightly.

On Wednesday, Goldman Sachs gs upgraded the software giant to buy from neutral and upped its price target to $68 from $60. The reason? Bellini and company think Microsoft msft shares will do very well in the upcoming year as the company’s Azure public cloud and Office 365 applications gain traction.

The authors added that the “steady albeit not spectacular performance” of Microsoft’s traditional Office and Windows franchises doesn’t hurt either. Windows and Office have been Microsoft’s cash cows for decades.

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Microsoft, like every other software company of a certain age, is navigating a tricky transition from selling highly profitable software that runs on corporate servers and PCs to the more modern Software-as-a-Service (SaaS) model pioneered by Salesforce.com. In that model the software vendor runs, maintains, and updates the software on its own servers and streams it out to customers over the internet. Business customers typically pay a subscription fee for that streamed software. Over the past decade, Microsoft Office 365 has been following in Salesforce’s crm footsteps.

Microsoft Azure is a different sort of animal. It competes head-to-head with market leader Amazon Web Services for selling or renting computing, networking, and storage capacity that it owns and operates for customers.

 

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In its 72-page cloud report, Goldman Sachs also estimated that revenue from public clouds in aggregate will more-than-quadruple to $140 billion in 2020 from $30 billion this year.

While you could quibble with those numbers there is no doubt that more businesses are putting more applications and storing more of their data in public clouds. Some do so to augment their existing data centers, others are foregoing their own data centers altogether.

The public cloud market, according to the report, will also become more concentrated between four major players: Amazon, Microsoft, Google googl , and Alibaba baba , the Chinese retail giant that is getting more aggressive in the market.

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Why so few? Not many companies can spend the multiple billions of dollars a year to build and maintain data centers around the world needed to run all that compute power. Over the past year or so, other companies that had set their sites on being public cloud providers, Hewlett Packard Enterprise hpe and VMware vmw among them, have backtracked on that strategy.