ICICI Bank shares are trading around Rs 366, after having hit a high of Rs 374 earlier in the day. The stock right now is up around 1 percent over its previous close.

CNBC-TV18 has learned from sources that the bank's Rs 15,000 crore Qualified Institutional Placement (QIP) has been subscribed over four times. Also, most of the bids have come in the Rs 355-358 range, compared to the floor price of Rs 351.36.

The allotment will be finalized on Friday. Around 42 crore fresh shares of ICICI Bank will come into the system as a result of the QIP. These shares will have a lock-in period of one year, meaning those who are allotted the shares in the QIB cannot sell those shares for a year.

Some fund managers who already own shares of ICICI Bank may offload a part of their holdings at the current price and subscribe to an equivalent quantity in QIP issue, which is priced at a discount.

That is the reason why stock prices are under pressure around the time of a QIP.