Both men admitted at the Downing Centre Local Court they used insider information to trade shares of resources company UCL Resources Ltd (UCL) earlier this year.
An investigation conducted by the Australian Securities and Investments Commission (ASIC) revealed that Mr Turner had received information that indicated UCL would announce a takeover bid from Oman-based Mawarid Mining LLC before the end of April 2013.
Mr Turner passed on this information to Mr Breen and instructed him to buy shares with his money on his behalf.
Mr Breen purchased the shares before 11 April 2013, which resulted in a profit of around $20,000. The trading benefited Mr Breen, Mr Turner and a third person.
Both men admitted the information they obtained about UCL was price-sensitive and not generally available.
The two men have been released on conditional bail and face a maximum penalty of 10 years' jail and/or a fine of $765,000.
The matter will return to Sydney District Court on 8 November 2013 for arraignment.
The Commonwealth director of public prosecutions is prosecuting the matter.
