The 20 cent issue opened on Wednesday at 17c and finished the day trading between 14 and 15 cents. At the close of today’s trade, the main stock was trading at 16 cents, and with the free attached option trading around 5c, it put investors slightly ahead of the money.

While chairman Greg Hancock declined to name the fund, other sources in the stockbroking community pointed the finger at a fund connected with the Packer family.

"I haven't managed to contact the fund involved," said Hancock, "so I don't really know what went on.

"The underwriter did a very good job on the day to support the stock," he said.

The sell down surprised many observers as the float was heavily oversubscribed. The assets Cooper has assembled are mainly minor positions in acreage held by Stuart Petroleum, which itself has enjoyed significant market support, having doubled in share price over the last two years without having drilled a single well in its South Australian tenements.

Stuart and a number of other explorers have been prevented from drilling due to Native Title disputes, which have been recently resolved.

Tolhurst Noall analyst, Peter Rudd, said the Sellicks well, scheduled for May, offered significant capital appreciation for Cooper.

“The fact that the offer was significantly oversubscribed, indicates the interest investors had in the IPO,” he said.

The managing director of another junior oil producer said he had wondered why the Cooper float had been so lacklustre given the overwhelming initial interest and added that it took the shine off the sector somewhat for the day.