Microsoft shares fell over 11 percent, the biggest plunge in more than four years.
It seems that shareholders are not happy after the Vole posted dismal quarterly results due to weak demand for Windows and poor sales of its Surface tablet.
The last time Microsoft faced a sell off this bad was January 2009, when the world's largest software company cut 5,000 jobs.
Analysts were worried it was good night Vienna for Microsoft's stock price. At one point the price fell by 12 per cent, making it the biggest fall since the internet stock bubble burst in 2000.
Microsoft is now worth $34 billion less than it was last Thursday.
Wall Street had thought that the company's strength with business customers would help it ride out a downturn in consumer PC sales. But as we have been saying for ages, companies don't buy the latest software in the middle of a recession.
Over the weekend there were mutterings that chief executive Steve Ballmer's new plan to reshape the company around devices and services is insane.
Nomura analyst Rick Sherlund said in a note to clients that Ballmer's glorious five year plan does not fix the tablet or smartphone problem.
Moves into devices received a $900 million hardware write-off for Surface RT and investors may not like the idea of wading deeper into this territory.
While Ballmer's push into devices and services has not happened yet, most people would expect Vole to be hurting at the moment. The PC market is still week and there is a pause ahead of the Xbox One release.
Still, investors must be hoping that Ballmer really does not get his way and carry out his charge of the Light Brigade into the guns of the consumer market.