Australian billionaire and climate activist Mike Cannon-Brookes has signaled an intention to target more companies with weak climate policies, after pushing through strategy reform at AGL Energy.

Cannon-Brookes, who is co-founder and co-CEO of Australian software firm Atlassian, is AGL’s largest shareholder, and earlier this year ran a campaign to end a planned demerger of the firm’s retailer and generator businesses.

In a recent interview at the Australia India Leadership Dialogue (AILD) conference, Cannon-Brookes argued that several companies lack detailed proposals on how they intend to meet their pledges on climate action.

“I could write most of their net-zero plans on the back of an envelope,” Cannon-Brookes said.

Cannon-Brookes added that he would likely repeat his tactic of becoming a firm’s leading investor in order to enact change.

“If the opportunity makes sense, if the company is not going in the right direction and offers a large opportunity,” similar action could be taken, Cannon-Brookes said.

The activist declined to identify any potential targets.