The Institute no longer discloses its funding sources, stating that it had ended its practice of donor transparency after experiencing the organized harassment of its donors. According to its brochures, Heartland receives money from approximately 5,000 individuals and organizations, and no single corporate entity donates more than 5% of the operating budget, although the figure for individual donors can be much higher, with a single anonymous donor providing $4.6 million in 2008, and $979,000 in 2011, accounting for 20% of Heartland's overall budget, according to reports of a leaked fundraising plan. Heartland states that it does not accept government funds and does not conduct contract research for special-interest groups.