The study, entitled Corporate Giving, It's Your Job to Do Something About It, shows that just over a third of companies have increased their level of support over the past three years, with fewer than one in seven giving less than they did three years ago.
Furthermore, most respondents to the study, sponsored by medical research charity Action Research, said that current levels of support would not fall in the medium term. A quarter believed they would increase.
The bulk of the pounds 18.9m donated by these companies in 1992 was given by companies employing more than 200 employees. But less than half of these go about it in a professional manner.
Indeed, the lack of enthusiasm for corporate trust funds adds weight to the common perception that most donations are not made in a tax-efficient manner.
But small businesses can also be significant contributors to charity; the 150 that took part in the survey donated a total of pounds 400,000, mainly to local charities. Although cash donations are the most popular form of giving, sponsorship, secondment and staff volunteering are also important.
The most common reasons given for charitable donations are improving company image, being seen as part of the local community and improving staff relations and morale.