Janet Yellen saved stocks from dropping below the recent up trend line.
"Financial market participants appear to recognize the FOMC’s data-dependent approach because incoming data surprises typically induce changes in market expectations about the likely future path of policy, resulting in movements in bond yields that act to buffer the economy from shocks. This mechanism serves as an importaI 0nt “automatic stabilizer” for the economy. As I have already noted, the decline in market expectations since December for the future path of the federal funds rate and accompanying downward pressure on long-term interest rates have helped to offset the contractionary effects of somewhat less favorable financial conditions and slower foreign growth. In addition, the public’s expectation that the Fed will respond to economic disturbances in a predictable manner to reduce or offset their potential harmful effects means that the public is apt to react less adversely to such shocks--a response which serves to stabilize the expectations underpinning hiring and spending decisions."