Over the past decade, Express Scripts has become the largest pharmacy benefit manager in the U.S. as the industry has consolidated. The company processes some 1.5 billion claims every year. The question now is if it can compete using its unique stand-alone business model with rivals like CVS Health that pursue a multi-pronged approach. Express Scripts has benefited from the wave of newly insured patients as a result of the Affordable Care Act and has significantly expanded its profit margins over the past five years, hitting 6.9% in 2015 compared to 5.4% in 2010. However, the company is at risk of losing its biggest customer. Express Scripts has been locked in a contract dispute with insurance giant Anthem, which accused Express Scripts of breach of contract and requested damages of as much as $13 billion. Anthem accounted for about 16% of Express Scripts’ revenue in 2015, and the likelihood of a contract renewal by 2019 is at stake.