The company said it had made the decision because of the continued deterioration of oil prices and a reduced appetite in the industry for more expensive deep water exploration.
In November Sound unveiled plans to buy Antrim with an all-paper deal worth £6.35mln or 3.44p per Antrim share.
The offer targeted Antrim’s 25% stake in the highly prospective Skellig Block, offshore Ireland. The transaction would also have given the combined firm a balance sheet with some £23mln of cash.
Antrim’s dismissed the approach and said the offer was not in shareholders' best interests; according to the firm’s management the offer did not significantly enhance shareholder value, nor did it recognise the value of the company’s assets and prospects.