Source: Google Finance. Chart updated at 12:30

We're watching with some amazement -- and fear -- as a massive selloff occurs on Wall Street. As of this posting at 12:15 p.m., the Dow Jones Industrial Average was down more than 393.22 points, or 3.62 percent, and the Nasdaq was off 85.12 points, or 3.54 percent. "If you hear screaming, it is just the capital markets," wrote Avvo CEO Mark Britton in a Tweet.

The downturn is obviously having a big impact on Pacific Northwest tech stocks. A little after noon Microsoft and Amazon.com were each down nearly three percent. RealNetworks had lost more than four percent of its value, while F5 Networks was off nearly four percent and Concur Technologies dropped just over two percent. it looks like one of the biggest local losers so far is Drugstore.com, which is down nearly 15 percent. Interestingly, Clearwire is bucking the trend, rising some five percent.

[Update 12:30 p.m: After a slight recovery, stocks are now headed down again. Click on the links above to see where individual stocks are trading. Meanwhile, TechCrunch reports that several financial Web sites are struggling to keep up as investors seek information about the selloff].

The swing in the Dow today has been more than 1,000 points, trading between 9,869 and 10,879. The Nasdaq has fluctuated between 2,185 and 2,407.

“I wish I had a definitive answer,” William Fitzpatrick, an equities analyst at Optique Capital Management, told the New York Times. “I think the information from Greece and Europe continues to get worse and that is what is weighing on investors.”