For the first time in two years, the Federal Reserve has decided to leave interest rates unchanged at 5.25 percent. Putting growth ahead of inflation, the Fed is taking the right step to prevent against a collapse in the housing market.  The central bank is clearly concerned about the economy as the statement recognizes that economic growth has been slowing.  The Fed is also fearing that the lagged impact of their rate hikes and higher energy prices will continue to restrain consumer spending.  Trading in the US dollar has been very volatile following the rate decision.  The US dollar sold off when the Fed announced their decision to pause but the greenback quickly recuperated its gains as the traders assessed the rest of the Fed's message and realized that the central bank left themselves the flexibility to restart their monetary tightening if needed.  The statement included a line that said "additional firming" may be needed if the economy heats up again or oil prices rise too excessively and inflation gets out of hand. However unless we have a serious shock, this is unlikely since the Fed made zero mention of the rise in unit labor costs.  In the meantime, dollar weakness could remain limited in the context of firm oil prices. The EUR/USD also failed to break above 1.29 as Lacker voted in favor of an interest rate hike. 

In the longer term, this is a significant shift in the Fed's monetary policy.  For all intensive purposes, they are done raising interest rates.  Only if the economy picks up significantly or oil prices break above $80 a barrel will Bernanke risk his credibility by changing his mind once again and lifting interest rates.

Kathy Lien is the Chief Currency Strategist at FXCM.