I mainly focus on the SPDR S&P 500 (SPY). It follows the movement of the top 500 stocks and therefore it gives a good indication about the Market's health. SPY moved up quite a bit since mid November and it's about time to take a break. I am not talking about a Market Crash just a healthy correction. Indicators I have been using showing that the momentum is slowing down and just the past week we also had a couple of days when noticaeble selling took place with higher volume. Of course the Market won't go straight down and reverse right away. There will be some up days so called oversold bounces. I also closely watch other Markets such as Emerging Markets (EEM) and European Markets (EFA) and I see the same correction is taking places in fact started earlier. International Markets a closely correlated so it's a good idea to keep an eye on them.