This study examines inequalities of school funding as exclusively generated by the parent community in urban public schools, and potentially illuminates a secondary impact of between-school segregation. For schools that are largely understood as free, the substantial injections of private financing into public schools indicate a concerning tension for fairness and equity. Using a census dataset of all public schools in one Australian capital city (n = 150), we compare reported parent 'contributions, fees and charges' and how they are patterned by measures of school disadvantage and advantage. We found a statistically significant relationship between private financing and measures of school-based advantage or disadvantage, over a four-year period. Advantaged schools generate up to six times greater income in comparison to disadvantaged schools over a four-year period, and we argue that the substantial gaps function as another form of 'compounded disadvantage' for residualised public schools and a tiered effect of segregation.