Forbes columnists M. Todd Henderson and Anup Malani make a compelling case for corporate philanthropy:

There is a tax efficiency to corporate giving. Both Pfizer and its shareholders lower their taxable income when the company donates Diflucan to Africa. If Pfizer instead maximized its profits, paid corporate income tax and then let shareholders make charitable donations to treat AIDS-related diseases out of their dividend checks, the money available for charity would be reduced, given the current 35% corporate income tax.

That's certainly true. The tax code is, I would argue, one of the few compelling arguments for charitable giving on the part of public companies. Without the tax benefits, I would argue that companies should stick to their income-earning knitting, delivering strong returns to shareholders who can then use the money to support the causes important to them.

Until 2003, Warren Buffett's Berkshire Hathaway (NYSE: BRK.A) had an innovative giving program that I think was a model of good corporate governance: the company designated a chunk of earnings for philanthropy each year, and then allowed each shareholder to designate a charity for their prorated share.

I'm just concerned about companies donating money to causes that are objectionable to some of their shareholders. For instance, Wal-Mart (NYSE: WMT) is a leading supporter of the Salvation Army, which has a long track record of discriminatory treatment of the gay community.

The government should amend the tax code to make it more efficient for companies to give their shareholders a say in corporate philanthropy.