The markets wrapped up another ugly day for stocks and exchange traded funds (ETFs) this afternoon.

The Dow Jones industrial average fell more than 2%, says Tim Paradis of the Associated Press, and it was down more than 300 points. The Nasdaq fell 1.9% and the S&P 500 dropped 2.9%.

Things today got off to a decent start, but that was quickly unraveled after the Philadelphia Federal Reserve said its survey of regional manufacturing activity registered at -20.9 from a revised reading of -1.6 in December.

That news was only followed by more bad news from the homebuilding and real estate sectors: housing starts were down and the building of new homes dropped 8% last month.

Now is a good time to review your sell strategy and make sure that you are sticking to your plan. It can be hard in times like these to keep your emotions from entering into the equation, but it’s one of the keys to being a successful investor.

We’re living in a different world now than the one we knew in 2007. Many of last year’s top performers are suddenly losing ground. If you’re holding on to those ETFs and remembering the good times, review them and see if it’s time to implement that exit strategy.

Tags: Dow Jones Industrial Average, Federal Reserve, Material ETFs, NASDAQ, Real Estate, S&P 500, Sector ETFs