Duration risk versus local supply channel in Treasury yields: evidence from the Federal Reserve's asset purchase announcements

The FOMC's announcements of Treasury purchase programs and the subsequent or contemporaneous statements by the New York Fed about the programs' operational details provide a sequence of natural experiments with the potential to shed light on the relative importance of the duration risk channel versus the local supply channel for the transmission of supply effects to the term structure of interest rates. Using intraday security-level data on Treasury securities, we conduct five event studies to document the presence of local supply effects and duration risk effects. Further, using our new measures of local supply surprise and duration risk surprise we quantify the average impact of these two supply channels on nominal Treasury yields for each of the five events. Finally, we also try to determine how the importance of these factors has changed over time and relative to the first Large Scale Asset Purchase program in 2008-09. We find that: first, once the pre-announcement market expectations are carefully controlled for, the duration risk and local supply channels together are responsible for a decline in yields averaging about 9 basis points per $100 billion over the course of these announcements; second, these two channels are almost equally important for the transmission mechanism of purchases, as on average each of these channels accounts for about half of the yields decline; third, the efficacy of these two channels does not seem to have declined over time; and fourth, the purchase and sale price reactions to the announcements are quite similar, a result potentially relevant for the unwinding of these programs.