Today, I read an article in The Age newspaper regarding a report by the ACCC of an increase in groceries' pricing by Coles and Woolworths due to fuel discount vouchers. If the report is true, then it supports the an observation that I have had over a number of years.
I have noticed that if the petrol station is near an affiliate supermarket, the price of the groceries from that supermarket is inflated to cover the cost.
In Australia, if you spend more than a threshold, typically $30, in a single transaction, you are entitle to a discount to an affiliate petrol station. The discount is usually 4 cents/litre, up to a maximum of 150 litres.
I have always had a suspicion that if the supermarket is attached to a service station, the cost of the groceries is higher to cover the cost of the discount. I was not able to detect the price increase. I feel that the pricing has only be very slightly increased, and is amortise over a period of time.
In some ways, I should be shopping at one of the other independent supermarkets like Foodworks or Ritchies. However, even these independent supermarkets are also offering fuel discount vouchers. So you cannot really escape it.
Assuming that all supermarkets has the same practice, it is almost compelling that you visit the affiliate petrol station so that the savings could be recuperated. If not, the supermarkets wins.
I have previous written about the discount fuel vouchers here.