Atlantic Philanthropies has banked its investment decisions on the philosophy that since a foundation’s grants generate a social return, those returns compound at a higher rate than its financial assets would, so more immediate grants will generate more social value than preserving the capital and making more grants later. This is the premise behind limited life foundations. Value, Time, and Time-Limited Philanthropy, highlights discussions among philanthropic leaders, advisors, and scholars about the social value a philanthropic initiative can be estimated to generate — taking into account direct outlay, social value, ripple effects, and durability — and whether, considering social utility, rates of return, and the compounding or erosion of value over time, the premise holds true for three Atlantic Philanthropies-funded initiatives. Initial study is showing that Atlantic’s short-term investments are paying off, in part because other foundations have taken a slower, more sustained approach, so there may be an important role for both approaches to funding to address systemic issues.