Doing good can pay off

Here's a piece that caught my eye at CSR wire, and this quote in particular made me wonder about the relationship between corporate responsibility and profit. "...Business Ethics magazine reports that companies on the S&P 500 stock index who make their annual 100 best corporate citizens list have higher sales and profits than those who don't". I should look into this before I make any assumptions, but I just wonder whether this is because more successful and profitable companies can afford corporate responsiblity programmes? They may not be profitable simply because they are 'good' corporate citizens.