5  See Lui and Longstaff (2004) and Stein (2005).
6  Some of the literature in this area would seem to imply that small policy moves explicitly motivated by a potential bubble, or similarly motivated public statements and regulatory changes, could effectively signal or  BIS Review 144/2008  3  Nonetheless, even if policymakers are confident that a bubble has emerged, the question of the timeliness of the call remains.