Australia's Woodside Energy said on Wednesday it had ended talks with Santos to create a possible AU$80 billion ($52.22 billion) global oil and gas giant.
Woodside said it would only pursue a deal that would add value for its shareholders.
Santos shares dropped 5% soon after the news was announced while Woodside's stock rose 2% on Wednesday.
"While the discussions with Santos did not result in a transaction, Woodside considers that the global LNG sector provides significant potential for value creation," Woodside CEO Meg O'Neill said in a statement.
Woodside had faced pressure from some investors not to pay a premium for Santos.
The deal would have been one of the largest corporate takeovers in Australian history.
If the merger had taken place, it would have created a major global liquefied natural gas producer that could attract more offshore investors as gas is seen as a key bridging fuel in the shift to cleaner energy.