Just what did Z Energy think it would achieve with another report dispelling the notion that petrol companies are quick to raise fuel prices but slow to drop them when oil prices fall? It talks of an urban myth, and probably thought of this as a useful public relations exercise. But if such a myth has currency, it is only among the uninformed. More to the point, any talk about how quickly or slowly the retailers react to international prices is a distraction from what should be the real focus of attention, that of the companies' margins.
Successive inquiries have discounted the idea that petrol companies indulge in opportunistic price gouging when international prices rise and fall. These have included one by consultants Hale & Twomey for the previous government and another in 2013 by the Institute of Economic Research. Their conclusion has been reinforced by work done by the Automobile Association and weekly monitoring by the Ministry of Business, Innovation and Employment. The work for Z Energy is simply an update of the institute's previous undertaking. Unsurprisingly, this supports its initial analysis, suggesting in addition only that the price change pass-through has become more rapid.
The petrol companies will trumpet this as evidence of competition at work. They can also point to a little more discounting over the past few months. But there the good news ends. Where Z Energy does not tread is the area of importer margins, the amount available to retailers to cover transport, distribution and retailing costs, as well as their profit margins. This has risen from a low of 15c a litre in 2008. Just before Christmas last year, it stood at 39.4c, higher than at any time since September 1990, when it was 48.68c, measured in inflation-adjusted dollars.
The upward trend has continued whether international fuel prices were high or, as recently, plunging. The petrol companies have made little attempt to justify it. Popular concern about whether prices were falling quickly enough served, in fact, as a useful smokescreen. The only ruffling of their feathers occurred early this year when the Energy and Resources Minister, Simon Bridges, said he was watching petrol retailers' margins closely. At the same time, however, he rejected a Labour Party call for a select committee inquiry into fuel prices, which would have turned up the heat a notch.
As it was, there was a dramatic slide in the margin after Mr Bridges' warning. Since then, however, it has again started to creep upwards towards 35c, around the average for the past year. In Z Energy's defence, its chief executive, Michael Bennett, has questioned the methodology used by the ministry to assess the margin. This, he said, was applicable when petrol companies were selling at the same price but took no account of discounts.