Greenspan was quoted on wire reports at that time (talking about inflation or something). It caused interest rates to spike a bit. -Eric Edit: the quote was "Low inflation suggests a measure pace of rate hikes..."
I heard it on CNBC shortly after it happened, with them quoting that as the cause for the bond spike. You can read more about it at the following link: http://www.foxnews.com/story/0,2933,121569,00.html -Eric