The proposed $20 billion takeover of Origin Energy by a private North American duo has now won support from all major proxy advisers, paving the way for a nail-biting lead-up to a decisive shareholder vote on a deal that is opposed by the electricity supplier’s biggest investor.

Ownership Matters on Friday joined larger peers Institutional Shareholder Services and CGI Glass Lewis in recommending a vote for the $9.53-a-share cash offer from Brookfield and EIG that has been rejected by 15 per cent shareholder AustralianSuper.