Using a unique dataset from Shanghai Stock Exchange, we study institutional trading behaviors in IPOs and post-IPOs. From the perspective of value-based or speculation, we find that, (1) institutional investors are flippers on the first day of IPOs, (2) trading by institutional investors and the active institutional investors (mutual funds or brokerage) is value-based, and (3) the net buys of institutional investors can predict the long term performance of IPO-firms and shows a negative relation with a bubble in future. Since individual investors are the opponent of institutional investors, our results mean that individuals are speculators in the market. Our study suggest that institutional investors are the sophisticated ones in the market and they can process information more efficiently, whose value-based trading can enhance market price discovery and is good for market stabilization.