Q. Where can I find information on corporate giving?

U.S. Corporations are not required to disclose their charitable contributions.
BusinessWeek has done an annual survey since 2003 (Late November early December) listing the largest 30 or so corporate contributors (cash and in-kind gifts). The information is based on about 200 returned questionnaires that BW sends to S&P 500 companies. This issue of BW also ranks the largest 50 individual charitable contributors.

Go to the database Business Source Premier and search:
business week as the SO Publication Name
and
givers in the TI Title