"AGL's old governance arrangements were developed when the company was a monopoly gas supplier, with few other business interests," said AGL chairman John Phillips.

"Its new constitution will be more consistent with the company's present position as Australia's largest downstream energy supplier, with businesses across Australia and in New Zealand and Chile."

Earlier this year, Mr Phillips warned that removing the cap would leave AGL vulnerable to takeover bids. Since then the stock has been one of the star defensive plays, rising from about $9 in January to more $10.

AGL is currently trading at $10.31, up by 9c on yesterday's trading.