Tilt Renewables’ two biggest shareholders have teamed up to make a takeover offer, just three months after one of them, Infratil, said it was unlikely to approve a move above 20 per cent.

But today Infratil and Mercury, which in May bought 19.9 per cent of the high tech windmill maker (ASX:TLT), announced a joint takeover offer of $2.30 a share cash.

The offer values the company at $720 million, a 31 per cent premium, and is conditional on approval from the Foreign Investment Review Board.

New Zealand energy provider Mercury NZ bought its first stake of 62.6 million shares from the Tauranga Electricity Consumer Trust and said it wanted to buy up to 26.8 per cent.

But 51 per cent Tilt shareholder Infratil said it was “unlikely to provide approval” for any other shareholder to move above the 19.9 per cent threshold.

Mercury controls the remainder of the Tauranga Electricity Consumer Trust shares, although has not bought them, and together the trio control 77.8 per cent of the Tilt register.

Tilt has been contacted for comment.

Hinting at why the two companies agreed to partner in the takeover, Infratil said in a statement Tilt had been intending to fund a proposed 336MW Dundonnell windfarm project it through a a debt and equity raising, “representing approximately 45 per cent of Tilt Renewables’ current equity value”.

“Infratil and Mercury’s offer provides shareholders with the opportunity to sell their Tilt Renewables shares at an attractive price,” the bidder said.

“Alternatively, in the event of a successful Dundonnell bid outcome, shareholders will be required to contribute a significant amount of new equity relative to their existing shareholding or be diluted in an equity raising.”

Tilting at a windmill maker

Tilt makes windwills that move to face the direction of the wind.

Mercury CEO Fraser Whineray says Mercury recognised the growth opportunity in wind and solar technologies.

Tilt has been one of the most successful companies in Australia and New Zealand to develop and commercialise renewable energy tech.

“Tilt is well established in Australia and New Zealand, in terms of its platform, expertise and development pipeline of wind and solar generation. It has a robust portfolio of operating wind farms, a strong management team with a proven track record and consented renewable generation projects which it can bring to market when conditions are right,” Mr Whineray said.

Tilt Renewables has about 11 per cent market share of installed wind capacity in Australasia, with a total installed capacity of 637MW across 8 wind farms.

Its development pipeline consists of 1,600MW of planning approved projects covering wind, solar and storage.

The stock has opened 23 per cent higher to sit at $2.15.