The Dow Jones Industrial Average (^DJI) had rallied 92 points as of 11:30 a.m. EDT. Microsoft (MSFT -0.42%) was the index's top-performing stock, while fellow tech stocs Micron Technology (MU -0.85%) also surged to the upside. BlackBerry (BB -2.05%), however, shed more than 2% early in the session.
Yellen reiterates Fed's commitment
Perhaps helping to fuel the Dow Jones' rise, Federal Reserve Chairwoman Janet Yellen on Monday reaffirmed the Fed's commitment to continue supporting the U.S. economy. While the central bank has been slowly curtailing its asset purchase program, Yellen said in a speech that it needed to remain aggressive, as there is still "considerable" slack in the U.S. labor market.
As long as the Fed remains stimulative, stocks could continue to move higher.
Microsoft continues recent rally
Microsoft shares have been moving to the upside in recent weeks, posting another 2% gain by late morning Monday. Microsoft's decision to release its Office software on the Apple iPad has been met with universal praise, and it appears to be working well -- Office has already climbed to the top of the App Store since being released late last week.
In order to edit or create documents, iPad owners need a subscription to Microsoft's Office 365. Given the popularity of Office, it seems that Microsoft may have picked up more than just a few subscribers over the weekend.
Micron rallies ahead of earnings
Micron Technology was one of the top performing stocks in the overall market, up 6.5% in early trading. Micron is set to release earnings figures later this week, and investors may be buying up shares in anticipating of a strong report.
Shares may also be rising in the wake of its addition to the Barron's 400, an index of 400 reasonably priced growth stocks.
BlackBerry hit by downgrade
Shares of the Canadian handset maker were likely falling due to a downgrade from Credit Suisse. Citing issues with the company's turnaround, analyst Kulbinder Garcha cut his rating on the stock to underperform and lowered the price target from $7 to $6.
In particular, Credit Suisse found issue with the company's free cash flow burn. Credit Suisse believes BlackBerry has enough cash to survive the next three years, but that further cash burn could make things difficult. Moreover, increased competition in the smartphone space will weigh on BlackBerry's hardware business.