If you're looking for a job, here's a list of successful, influential corporations you might want to work for. That is, as long as you don't ask too many questions.And a dozen more.
LexCorp (DC Comics)
Hailed as one of the largest, most diversified multinational corporations in the world, it also happens to be founded by Lex Luthor, who runs it with his characteristic ruthlessness. The list of cities and countries where the corporation has holdings is basically as long as the list of cities and countries on Earth, and the number of companies controlled by LexCorp is almost as long and just as varied. Unfortunately, as of One Year Later, with Lana Lang acting as CEO, the corporation seems to be heading towards bankruptcy. The "No Helping Superman" rule still applies to all employees, however.
Weyland-Yutani (Alien franchise)
Perhaps the gold standard of evil megacorporations, Weyland-Yutani's main gig is merciless profiteering, no matter what (or who) needs to be sacrificed in the process. (Fun fact: Their logo can be seen on some of the weapons in Firefly and they're said to be a client of Wolfram and Hart in Angel. Maybe this has something to do with the fact that Joss Whedon wrote Alien Resurrection.)
Cyberdyne Systems Corporation (Terminator films)
While the corporation is said to be benign in the first two films, manufacturing parts for bigger companies, they then make the mistake of creating Skynet, a system of artificially intelligent supercomputers that control (among other things) nuclear missiles. This was not a smart move. In fact, it's just un-smart enough to warrant Cyberdyne's inclusion on this list....