IPO initial returns reached astronomical levels during 1999-2000. We show that the regime shift in initial returns and other elements of pricing behavior can be at least partially accounted for by a variety of marked changes in pre-IPO ownership structure and insider selling behavior over theperiod which reduced key decision-makersacirc;not;quot; incentives to control underpricing. After controlling for these changes, there appears to be little special about the 1999-2000 period, aside from the preponderance of internet and high-tech firms going public. Our results suggest that it was firmcharacteristics that were unique during the acirc;not;Sdot-com bubbleacirc;not;? and that pricing behavior followed from incentives created by these characteristics