An estimated $200 million in tax-exempt funds were donated to Jewish residents in the West Bank over the last decade, supporting settlements which are at odds with the current US's administration's policy, the New York Times
Washington does not allow Israel to spend US aid on West Bank settlements, but tax breaks are allowed on charitable donations to the area.
Former US ambassador to Israel Daniel C. Kurtzer was quoted by the New York Times
as saying that the issue was politically delicate. “It drove us crazy,” he said. But “it was a thing you didn’t talk about in polite company.”