CANBERRA, Australia (AP) — Australia's largest electricity generator, AGL Energy, has rejected an 8 billion Australian dollar ($5.8 billion) takeover bid from tech billionaire Mike Cannon-Brookes and Canadian investment firm Brookfield, who want to accelerate Australia’s largest electricity generator’s transition away from coal-fired power.

The Australian founder of software company Atlassian and Brookfield made the preliminary and non-binding offer of AU$7.50 ($5.39) per share on Saturday, AGL said Monday.

The target’s board said in a statement the offer “materially undervalues the company on a change of control basis and is not in the best interests of AGL Energy shareholders.”

Cannon-Brookes said he would continue negotiating with AGL's board.

“Look, it’s obviously disappointing,” Cannon-Brookes told Australian Broadcasting Corp.

“We’ve been trying to work with the board through the weekend and we’ll continue to move forward,” he added.

Federal Energy Minister Angus Taylor said energy companies, as providers of an essential service, had a responsibility to put consumers first.

“The key to this is balance,” Taylor said.

Australia’s Clean Energy Regulator said AGL is the nation’s largest greenhouse gas polluter, accounting for 8% of the nation’s total emissions.

AGL's share price jumped nearly 12% on Monday, while shares in Atlassian were down almost 2%.