Shared equity homeownership initiatives provide below-market homeownership opportunities to income-eligible families in return for a share of the owner's potential capital gains at resale. This case study analyzes affordability, personal wealth, security of tenure, and mobility outcomes for A Regional Coalition for Housing (ARCH), which operates in eastern King County, WA. ARCH owners realized very high returns, but resold homes saw a decrease in affordability over time. Foreclosure rates for ARCH homes are well below the area's already-low average. And resale restrictions did not appear to limit mobility, allowing owners to leave with the equity they had built in ARCH.