The a2 Milk Company (a2MC) became the most valuable company listed on the New Zealand stock exchange in 2018 by capitalizing on a biochemical discovery related to the protein composition of cow's milk. Because many people find the A1 protein difficult to digest, and that protein may be related to other health problems (e.g., diabetes), a2MC sells dairy products containing the A2 protein only primarily in Australia and China. With sales of NZ$730 million in 2017 and a desire to grow, a2MC formed a strategic relationship with Fonterra, the world's sixth largest dairy company, in February 2018. But one month later, Nestle, the world's largest dairy company, confirmed that it had begun selling A2 infant formula in China, and people speculated that it would start selling A2 products in Australia and New Zealand later in the year. a2MC's retiring CEO Geoffrey Babidge and newly appointed CEO Janyne Hrdlicka must decide how to respond to Nestle's entry. Can this successful entrant become an incumbent with a sustainable competitive advantage?