Commerce Commission v Fonterra Cooperative Group Ltd

This Supreme Court case sits at the intersection of competition policy, regulated supply obligations and pricing methodology. Fonterra had a statutory obligation to supply raw milk to independent processors. If the parties could not agree a price, a default formula in the regulations applied.

The fight was over one ingredient in that formula: the “cost of capital rate” used to calculate annualised share value. The Commerce Commission said the regulation pointed to equity capital. Fonterra said it could use WACC, a weighted average of debt and equity costs. The Supreme Court agreed with the Commission and held that the capital referred to in regulation 9(1) was Fonterra’s equity capital.

The dairy industry restructuring legislation allowed the main co-operatives to amalgamate into Fonterra. Because Fonterra became overwhelmingly dominant in the market, Parliament also imposed regulation to preserve contestability. One of those controls required Fonterra to supply raw milk to independent processors.

The regulations set a default milk price if Fonterra and an independent processor did not agree a price. That default price was built from a formula. The formula had to separate, or “unbundle”, two things that were mixed together in Fonterra’s payout to farmer-shareholders: payment for milk and the return on their shares.

That unbundling mattered commercially. If the return on shares was treated as lower, the milk component was treated as higher. A higher milk component meant a higher default price for independent processors. The Commission argued that Fonterra’s use of WACC wrongly reduced the return on equity and therefore wrongly increased the default milk price. Fonterra argued that WACC was a recognised cost of capital rate and that it had used that rate in calculating the share price, so regulation 9(1) picked it up.

The legal issue was narrow in wording but important in effect. Regulation 9(1) said the discount rate used to calculate annualised share value had to be the same as the “cost of capital rate used by [Fonterra] in calculating the price of a co-operative share”. The question was what kind of capital that phrase referred to.

Fonterra’s position focused heavily on the word “used”. It said that because WACC was used in its share valuation process, WACC was the relevant rate. The Commission said that approach asked the wrong question. First, the court had to decide what “cost of capital rate” meant in the regulation. Only then could it ask whether Fonterra had used that kind of rate.

So the real issue was whether the regulation referred to equity capital alone, or to enterprise capital more broadly, including debt. The answer would determine the proper discount rate for annualised share value and therefore affect the default raw milk price.

The Supreme Court allowed the appeal and declared that the capital referred to in regulation 9(1) was Fonterra’s equity capital. In other words, the relevant rate was the rate applicable to equity capital, not WACC.

The Court gave several reasons. First, it said the meaning of regulation 9(1) could not be driven simply by the fact that Fonterra had “used” WACC somewhere in its valuation process. Fonterra had used multiple capital rates in that process, including rates for equity, debt and the weighted average. The regulation could not sensibly be read as letting Fonterra choose whichever one suited it.

Secondly, the Court said WACC had been used to calculate enterprise value, but debt was then backed out before arriving at share value. That mattered because the regulation was concerned with annualised share value and the return on shares. Thirdly, the Court read regulation 9(1) together with regulation 9(2). Both provisions were aimed at setting an appropriate discount rate for annualised share value, so they should work symmetrically. That pointed to equity capital in both cases.

Most businesses will never deal with raw milk regulations. But many businesses do operate under rules that prescribe how a price, fee, rebate, member return or adjustment must be calculated. This case is a strong reminder that legal formulas are not always the same as accounting formulas.

If your business is in a regulated sector, a common mistake is to start with your internal model and then assume the law adopts it because it is standard industry practice. The Supreme Court took the opposite approach. It started with the legal purpose of the regime and asked what kind of rate made sense for that purpose.

That matters in sectors such as utilities, agriculture, franchising, financial services, transport and any market where a dominant player has mandatory dealing obligations. It also matters for co-operatives and member-based businesses where payments can bundle together different economic components. If a rule is trying to isolate one component, your methodology must match that legal objective.

If your business uses a statutory or contractual formula, review it as both a legal and commercial document. The safest approach is to test each input against the purpose of the clause or regulation, not just against your spreadsheet logic.

This is especially important where your business has market power, supplies competitors, deals with members or franchisees, or calculates payments that combine several economic elements. A method that looks normal in finance terms may still fail if it distorts the legal objective of the formula.