Corporate giving to the arts fell by 17 per cent between 2007/08 to 2009/10, according to a new index set up to measure the state of the arts sector.
There are 20 different indicators, including how much is given to the arts per person in the UK and levels of participation in the arts.
The index shows that the value of corporate donations to arts organisations fell from an average of £2.65 per UK resident in 2007/08 to £2.20 in 2009/10, a fall of 17 per cent.
Individual giving was down 13 per cent, from an average of £6.27 per UK resident to £5.48. However, the value of grants from trusts and foundations increased by 2 per cent, from £2.31 per person to £2.36.
Corporate giving fell from £161.7m in 2007/08 to £144.1m in 2009/10. Individual giving fell from £382m to £359m in the same period. And grants from trusts and foundations increased from £141m to £154m.
"Given the government's stated intention that cuts to the arts should be supplemented by philanthropic donations, these UK and US trends are worrying," the report says. "The index will help to measure the effectiveness of new funding schemes designed to help the sector find philanthropic support."
It found that public funding through Arts Council England and local authorities remained stable through the three years covered by the index. But it points out that the figures did not include cuts made this year.
The index found large regional differences in the amount given to the arts. For example, public funding for the arts per person in 2009/10 ranged from £9.76 in the east of England to £36.71 in Greater London.
"Looking ahead, we expect the double squeeze of 15 per cent cuts to Arts Council England funding and a 28 per cent fall in local authority funding to bite hard," the report says. "The impact of local cuts on the wider economy will begin to be felt more strongly."
The National Campaign for the Arts says it plans to publish the index every year against a base year of 2007/08.