With its charter school market share expected to reach nearly 40 percent by 2018–19, Newark, N.J., is approaching the point where the effects of charter sector growth on traditional schools are impossible to overlook. This case study, commissioned by Startup:Education, examines the forces that helped grow the charter sector in Newark, and the opportunities and issues that arise for both charters and the district when the charter sector grows large. In Newark, philanthropic and bipartisan political leaders have teamed up to increase high-quality education options for all Newark students by both growing the charter sector and transforming the district into a financially sustainable model of effective reform. This case study explores what happens when a rapidly growing, high-quality charter sector pushes district reform, and the lessons other cities and districts with a growing charter presence can take from Newark..