Origin Energy Ltd.’s largest shareholder AustralianSuper said it will vote against the revised A$19.1 billion ($12.5 billion) offer for the utility by a Brookfield Asset Management Ltd.-led consortium.

“This latest low-ball offer strengthens AustralianSuper’s view that the offer remains substantially below our estimate of Origin’s long-term value,” the pension fund said in a statement. “AustralianSuper is resolute the value and future value of Origin is better in the hands of AustralianSuper members and other shareholders than a private equity consortium planning to shortchange them.”

AustralianSuper confirmed it now owned more than 17% of Origin, in the statement.

Origin asked investors to vote on a revised offer on Dec. 4, postponing a scheduled meeting for Thursday after proxy results showed the existing proposal would fail. Under the amendments, institutional investors would be given an opportunity to re-invest into Origin’s energy generation and retailing business after the unit is sold to Brookfield as part of the existing offer, the target said.