Mathieson owns 6,141,605 shares, or 6.21%, in the company that were acquired from 19 November 2010 to 25 June 2012.
IPB started trading on the ASX on Tuesday, 30 April 2013, offering investors exposure to two highly prospective offshore Browse Basin oil and gas tenements.
Notably, the first well on its Pryderi oil prospect in WA-424-P is fully funded by farm-in partner CalEnergy, a fully-owned subsidiary of Berkshire Hathaway's MidAmerican Energy Holdings Company.
This targets mean recoverable prospective resource of 40 million barrels and has an overall 45% chance of success.
IPB has $4.1 million in cash at hand.
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