Charitable organisations play an important role in providing services for communities, with most reliant on the support of individuals. Recessions internationally have increased the challenge of attracting and retaining supporters. The support behaviour shown toward charities is considered different to that displayed in for-profit markets, thus requiring specific models to explain behaviour. We check this assumption with online data of a broad range of support activities to charities over six months. We find supporters are polygamous rather than solely loyal, with around 5 charities supported. This challenges assumptions held by charity marketers and suggests the model can help marketers to inform their decisions to optimise precious marketing resources in the charity sector.