Based on the provided reference regarding funding the United Nations, the United States is the largest donor to the overall UN budget, which includes various UN agencies and programs.
While the provided reference focuses on general UN funding, it's reasonable to infer a strong likelihood that the United States is also among the largest, if not the largest, donors to the United Nations Development Programme (UNDP), given its overall significant contribution to the UN system. However, without direct confirmation regarding UNDP specifically, this cannot be definitively stated based solely on the given source.
It is important to note that donor rankings can change annually depending on various factors including economic performance and national priorities. For the most up-to-date and accurate information regarding largest donors to the UNDP, consulting official UNDP reports and publications is recommended.