The results claim that supply effects do play a substantial role in driving longer-term interest levels. There are two caveats on these results. First, if debt managers seek to improve the maturity of debt when longer-term interest levels are expected to go up later on, our results could be somewhat upward-biased. But we remember that in the time we study, many changes in the maturity of debt were led by legislation, instead of any short-run response to advertise conditions (e.g. in 1976 and 2001). And, second, if we extend the estimation sample there is some proof structural instability from 2008 onwards, which could very well be hardly surprising, and additional motivates the usage of the pre-crisis period.