CAF AMERICAN DONOR FUND - A dual qualified Donor Advised Fund for your dual US and UK taxpayer clients With over 20 years’ experience, we offer philanthropy services for dual US and UK taxpayers. The CAF American Donor Fund can help your clients maximize the value of their gifts to charitable organizations. Our service enables your clients to claim eligible US and UK tax relief on their global giving, including adding 25% through UK Gift Aid where applicable.