The second public offering of Punjab National Bank (PNB) was oversubscribed by two times within minutes of its opening today.Against the offer of eight crore shares, bids were received from investors for over 16 crores, investment bankers said.The bidding for the 100% book-built issue with a price band of Rs 350-390 per share would close on March 11.Of the shares offered, PNB has reserved 10% or 80 lakh shares for the existing small shareholders and an equivalent proportion for employees. The remaining 6.4 crore shares would be offered to the public.A minimum 35% of the net offering has been reserved for retail individual investors who can bid for equity shares up to Rs 1 lakh in value.Qualified institutional buyers (QIBs) are allowed to bid upto 50% of the net offering whereas minimum 15% has been reserved for non-institutional bidders.After issuing eight crore shares, government's holding in the bank would come down to 57% from the present 80% and would improve its capital base to meet the stringent Basel II norms and increased business requirements.At the lower end of the price band, the bank is expected to raise Rs 2,800 crore, while at the upper end, the bank aims to garner Rs 3,120 crore.The merchant bankers of this second public offer are DSP Merrill Lynch, JM Morgan Stanley, Kotak Mahindra Capital, I-sec and Enam Financial Services.