The point isn't easily settled, it seems:
I am having a hard time to find financial statements from Debian.
Ubuntu, or rather Canonical, being a private company, doesn't seem to release financial information. The Ubuntu main page doesn't even provide a 'donate' link anymore.
Which leaves RedHat, at last. A public company, of course[0]:
Operating profit 2014: $ 1.3e9
Net total income 2014: $ 178.3e6