The Prince of Wales received a private income from the Duchy of Cornwall of nearly £6 million this year, but was criticised for not publishing an annual report in his first year as heir to the throne.
William inherited the Duchy landed estate after the death of his grandmother the late Queen and the accession of his father the King, and is now entitled to its surplus profits every year.
Republic, which campaigns for an elected head of state, called on William to report his income and expenditure in full, and for his Duchy income to be given to local communities across the country instead.