Its worse than that. A corporation starts a charity or gives 100k to one. Real nice right? Nope.

They will:

1. use that to decrease their tax burden, robbing the commons of their share of taxes to repair the infrastructure their semi-trucks and businesses disproportionately use and tear up, the public educated, pre-literate workforce they have access to, and then...

2. they ADVERTISE how noble they are, spending millions upon millions in ad buys to tell you what how awesome they are for donating that 100k. They use the guise of what is supposed to be giving with no expectation of return, ie "charity," as a marketing strategy, and then...

3. They use such initiatives as lobbying tools to explain why their industry doesn't need to be taxed to institutionally, societally address the issue that is currently subject to the transient whims of charity.

There is nothing a publically traded corporation does that isn't done out of greed, that isn't calculated to provide more return than dispursment. Nothing.

Charity with any expectation of return, beyond a warm fuzzy feeling inside, isn't charity at all, but there is a word for it: a transaction.