Microsoft's shares scaled levels last seen in the dotcom boom on Tuesday following reports that the company plans to unveil an iPad version of its Office software suite, potentially generating billions of dollars in revenue.
Reuters reported on Monday that Microsoft Chief Executive Satya Nadella would unveil the iPad app at an event on March 27 as part of the new CEO's "mobile first cloud first" strategy.
The event will be Nadella's first major public appearance since his appointment last month.
Microsoft shares rose as much as 5 percent to $39.90 on Tuesday, adding $15 billion to the company's market value. At that price, the stock was up about 10 percent since the announcement of Nadella's appointment on Feb. 4. The shares last touched $40 in July 2000.
The stock ended nearly 4 percent higher on Tuesday. (Click here to track Microsoft shares in after-hours trade.)
Microsoft has had iPad and iPhone versions of Office primed for several months now, sources told Reuters, but the company has dallied on their release due to internal divisions, among other things.
Analysts said the lack of an Office version for the iPad may have robbed Microsoft billions of dollars in revenue.
"We estimate that if 10 percent of the iPad install base were to subscribe to Office then this could add 15 million subscribers and generate $1.1 billion to $1.5 billion in consumer Office subscription revenue per year," Bernstein Research analyst Mark Moerdler said in a note on Tuesday.
(Read more: iPad for Office to be unveiled this month)