New York City’s charter school sector is distinguished by its size (second-largest enrollment of any district in the nation), a record of strong student performance, and the high percentage of schools “colocated” in a district public school facility. Whereas only 25% of charter schools nationwide are colocated, two-thirds are in New York. Colocated charter schools in New York City are not required to pay rent for use of the district school space, but some argue that they should be required to do so. This paper examines the potential impact of requiring colocated charter schools to pay rent. It finds that charging rent in line with the IBO’s recommendation would have forced 71% of colocated charters into deficit in 2011–12, the last year for which data are readily available. Over the last decade, colocation played a key role in facilitating the expansion of New York’s charter school sector, which, rigorous studies have found, tends to outperform New York City district public schools.