Charities are considering what message to give to richer donors in the light of last month's Budget move to raise the higher rate of income tax next year from 40 to 50 per cent for people earning more than £150,000.
From April 2010, people in this pay bracket who choose to claim back their personal tax break on Gift-Aided donations - the difference between the standard and higher rates of tax - will receive more: they will be able to reclaim £37.50 for each £100 donated.
If they choose to donate the difference to the charity through their tax assessment forms, a £100 donation could yield £176.28, compared with the current £160.25.
"Although higher-rate taxpayers earning more than £150,000 a year will no doubt be unhappy at the prospect of paying more tax, it could have a positive impact on their personal tax relief on charitable donations," said John Low, chief executive of the Charities Aid Foundation.
If higher-rate taxpayers do donate the difference between the two rates of tax, charities could reap the biggest rewards in the 2010/11 fiscal year, when the new tax rate is introduced and transitional relief on Gift Aid still has a year to run.
The relief entitles charities to continue to receive 28p per pound donated despite last year's fall in the basic rate of tax.
Barry Gower, director of Gift Aid consultancy Gain, said charities should consider asking major donors who are planning to give early next year to hold off until the 2010/11 tax year to maximise the value of their donations.
"Charities need to work out how to maximise their donations by making the best use of the higher rate of Gift Aid," said Gower.
Beth Breeze, researcher at the Centre for Charitable Giving and Philanthropy, said more charities were employing major donor fundraisers and that "a potential window of opportunity" had opened.
Louise Richards, director of policy and campaigns at the Institute of Fundraising, agreed. "The new higher tax rate could well be an incentive for more engaged donors," she said.