The Charity Commission will take no further action over a donation of about £2.5m to one of Prince Charles's charities.
The commission, which regulates charities in England and Wales, said: "We have assessed the information provided by the charity and have determined there is no further regulatory role for the Commission."
The decision was made following reports that Prince Charles was handed €3m in cash stuffed into bags by a Qatari sheikh.
The payments were allegedly accepted by the heir to the throne during private meetings between 2011 and 2015, The Sunday Times reported.
The prince's office said the money was handed over to one of his charities who carried out appropriate governance and gave assurances that all the correct processes were followed.
The commission was considering whether a review into the donation was needed, but has now said it will not take further action.
It added that it has "no concerns" about the governance of the prince's charity and that trustees submitted information via a serious incident report.
In response to previous reports, a senior palace source said the prince accepting bags of cash for his charity "would not happen again".
The Sunday Times said the three lots of money, which totalled €3m, were handed to the prince personally by Qatar's former prime minister Sheikh Hamad bin Jassim bin Jaber Al Thani, known as HBJ.
The paper said there was no suggestion that the payments were illegal but anti-monarchy campaign group Republic said it wrote to the Charity Commission to demand an investigation.