NEW YORK, NY -

Thursday was a bad day for the Dow. Stocks closed down more than 353 points, the second day of a major sell-off that left the market behind by more than 500 points.   So, should you worry about your 401-K?

From the opening bell, Deja-vu of plunging stocks- the worst day of the year on wall-street with the Dow dropping by more than 350 points at the close. Investors say the drop is largely due to, of all things, good news about the economy.  Federal Reserve Chairman, Ben Bernanke announcing Wednesday that if the economy continues improving, the Central Bank could soon begin winding down its stimulus program which pumps 85 Billion dollars into the market each month to keep it afloat.

Jonathan Corpina,  Senior Managing Partner for Meridian Equity Partners say's, "We've had training wheels on our economy for quite some time now and now we're getting word that these training wheels are going to have to come off,  slowly come off and we're going to have to see if we can ride this bike on our own."

The market uncertainty has had some impact leading to mortgage rates climbing above 4 percent for the first time in a year, but ABC News Chief Business & Economics Correspondent Rebecca Jarvis says, "Traders on the floor of the stock exchange are not worried." 

"The Dow so far this year is still up more than 10 per cent and we're still just 5 per cent below the all time record high that we hit last month."

Some traders say this kind off sell-off is to be expected after what has been a roller coaster week on wall street  with the dow up or down by triple digits each day.