The government is allowed to sell its stake in Citigroup as of today. $30 billion worth of new supply would not be a positive for the market and would likely hasten a correction. If they decide to go ahead with the offering this week a move in the market could be exacerbated by options expiration. While it is likely the government will divest its stake as long as Citigroup stays at these level, the government is notoriously slow moving so trying to figure out the timing of an offering is tricky.
Putting Citigroup aside, the market is starting to look a little tired. New 52 week highs contracted significantly yesterday and the Russell 2000 lagged. The biggest problem with a correction is that too many market participants seem to be looking for one. Maybe yesterday's comeback will finally make the last holdouts come to the bull side and clear the way for a correction.