Short term run up in IPOs...anecdotal evidence fits historical

In class we teach that IPOs are very risky and have historically been underpriced in short run and then overshoot their value and are overpriced in longer run. (see Ritter's work on this)The standard academic explanation for this is that with a float lower than shares outstanding the stock is very difficult to be shorted (See Bradley and Jordan 2002) and there are no options for a period so