The markets continued to fall on Tuesday, as fears about the fiscal cliff are still weighing on equities. The Dow Jones Industrial Average (DJINDICES:^DJI) fell more than 58 points, or 0.46%, to close the day at 12,756. Only six of the Dow's 30 components were positive today.

Leading the Dow's decline was Microsoft (NASDAQ:MSFT), which plummeted more than 4%. The sell-off resulted from the company's announcement that it's letting go of Steven Sinofsky, president of the Windows operating system division. Sinofsky, a 23-year veteran of the company, was reportedly asked to leave after numerous disagreements with other executives, including CEO Steve Ballmer. This division is vital to Microsoft's future success, and investors are uncertain whether replacements Julie Larson-Green and Tami Reller are up to the task. 

Cisco Systems (NASDAQ:CSCO) was one of the few bearers of good news in the Dow today, reporting what was viewed as an impressive quarter after the bell. The tech giant beat analyst estimates on both revenues and earnings per share in the quarter. Shares were trading as much as 7% higher in after-market trading on the news.

In other tech news, game company Zynga (NASDAQ:ZNGA) announced that current CFO David Wehner will be leaving the company to accept a "senior finance position" with social networking giant Facebook (NASDAQ:FB). Zynga also reiterated its FY 2012 financial outlook; shares traded modestly higher in after-market sessions. 

But Facebook's new hire likely wasn't what most of its investors had on their minds today: Tomorrow, a third "lock-up" period will end for the company, allowing early investors and employees to sell up to 773 million shares. This is the end of the largest lock-up period yet for Facebook. The first lock-up period ended in August and, though only 270 million shares were freed up, Facebook shares fell 6% that day. Shares dropped 1% today in anticipation of the new selling pressure. 

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