FROM AISLES TO OLIGOPOLIES: NEW INSIGHTS ON SUPERMARKET COMPETITION IN

The recent period o high infation has renewed concerns about the state o competition in the sector, particularly in terms o the dominance o Coles and Woolworths. [...] Separately, the Federal opposition has proposed the introduction o new powers to allow the breaking-up o the major supermarket chains. [...] This proxies the set o nearby competitors the store aces.7 I ocus on supermarkets located in NSW and the ACT, allowing or analysis over a wide geographic area whilst balancing the time cost o geocoding the transactions. [...] Grouping these consumers by the brand o primary store they visited in the rst month, I calculate their propensity to revisit a primary store o the same brand in the subsequent ve months. [...] Consumer inertia impacts the eld o competitive rivalry between stores Which stores are the strongest competitive rivals? Using the locations that consumers visit or their primary shops over time, I build a network o stores linked by the customers that they share.15 This provides a non-parametric estimate o the ’ eld o competitive rivalry’ between stores, generated by revealed pre erence o s.