Microsoft's share price cracked $40, setting an 11-year high in trading on Thursday.
The company's shares closed at $40.33, up nearly 3% for the day. The last time Microsoft was above $40 was in February 2003, just before its last stock split.
Most Wall Street analysts have pegged the climb in Microsoft shares to news earlier this week that CEO Satya Nadella, who took over from Steve Ballmer six weeks ago, will lead a March 27 press conference that will be "focused on the intersection of cloud and mobile computing," a phrase reminiscent of his first day's message to employees, customers and investors that he would make Microsoft a "mobile-first, cloud-first" company.
Along with that news, speculation started that Nadella would use the event to announce Office on the iPad, and put an end to years of talk about whether -- and if so, when -- the company would dump its strategy of linking the productivity suite with Windows in an effort to bolster the latter's chances on tablets.
Wall Street has been clamoring for Microsoft to bring Office to the iPad, believing that the move would unlock billions in revenue for the Redmond, Wash. company. Activist investment firm ValueAct used that argument last year, along with others, to pressure Microsoft to give it a seat on the company's board of directors.
Microsoft added G. Mason Morfit, president of ValueAct Capital, to the board last week, fulfilling its part of a deal struck last year to fend off a proxy fight.
Shares have surged 7% since last Friday's closing, increasing Microsoft's market capitalization to $336 billion, an increase of approximately $23 billion in just four days.
Ironically, the man who last year said that Office on the iPad would appear only after a touch-first version launched for Windows 8.1, and who dragged his feet for years over whether to pull the iPad trigger, benefited substantially from the increase in share value.
Former CEO Steve Ballmer's Microsoft portfolio of 332 million-and-change shares were worth $876.5 million more at the close bell Thursday than they were last Friday.
Microsoft's share price has climbed 7% since last week, largely, say analysts, on the basis of talk the company will announce Office for Apple's iPad next week.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed. His email address is firstname.lastname@example.org.
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This story, "Talk is not cheap: Microsoft adds $23B to market cap on rumors of Office for iPad" was originally published by Computerworld.