Lead underwriters Goldman Sachs (GS) and Citigroup (C) priced the Mastercard (MA) IPO Wednesday night at $39, below the expected range of $40 to $43 per share. On Thursday shares opened at $40.30 and then soared another $6 to close at $46 each. That trading action is quite baffling if you ask me.

Usually where the IPO is priced tells you how strong demand is, and subsequently, how well the stock will do upon opening for trading. The $39 pricing indicated to me that the smart money wasn't very enthusiastic about the deal. Then less than 24 hours later the stock is fetching $46. If demand was that strong, they easily could have priced it within the proposed range.

The conclusion I draw from this is that the smart institutional money wasn't sold on the price, but retail interest after the stock opened was strong. Following the retail crowd is rarely a good strategy, so I will put more weight into the $39 pricing than the $46 first day closing price. The stock's valuation also supports the cautious view. Mastercard earned about $2 per share in 2005, so the P/E is north of 20x, very high for a financial services company.