Kostak rates

Kostak rates!!
Kostak rates refers to IPO and listing of stock in stock market
The investor who have been alloted the shares on IPO application sell their "lot of shares" in grey market before listing of the stock takes place in stock market.
Here investor having a motive to make quick gains fears that on stock listing prices of new issue would see a downfall. Where as there are other individuals you would like to purchase these shares from these investors but cant wait for stock listing as they have a opposite view.. they foresee that on listing stock would see upward moment or stock is a undervalued in its first offer price by the company...