What is perhaps more surprising in Figure 1 is that the three-month Treasury yield was also partially or completely insensitive to news in 2003 and 2004, a period when the federal funds rate target and three-month Treasury yield never fell below 1%. However, the Fed had lowered the fed funds rate to 1% in June 2003. At the time, a fed funds rate below 1% was considered disruptive to markets (see Bernanke and Reinhart 2004). So, rather than lowering the rate any further, the FOMC switched to a policy of managing the public’s expectations for monetary policy through language used in FOMC statements and other communications. Thus, even though the fed funds rate was not at the zero lower bound, the three-month Treasury yield behaved as if it were constrained by a floor of 1%. The fact that the empirical method in Swanson and Williams (2013) picks up this monetary policy constraint is noteworthy.