When it comes to Marvel Comics, bad guys come in all shapes and sizes. Aliens, wizards, demons, and androids have all taken a swing at Marvel's heroes, and while they - along with piles of super-powered villains - keep coming back for more, the biggest threats in Marvel are more and more often companies; businesses whose scale and practical deniability allow them to carry out acts of evil and then carry on making money as if nothing happened, ensuring they continue as threats long past whichever CEO actually gets scooped up by the Avengers. But which of Marvel's evil companies is the most dangerous, and how can they possible be deadlier than the death-worshiping Mad Titan Thanos?
In asking which of Marvel's companies is most evil, we're not just talking about evil business-people in the Marvel Universe. While Ezekiel Stane has menaced Iron Man and Black Panther with his fortune, and Walter "the Mogul" Declun was a bad enough CEO of Damage Control to get himself stabbed by Wolverine, these are mostly bad individuals whose otherwise normal companies often went straight or folded without them. No, in finding Marvel's most evil company, we mean those organizations that are bad to the bone.
Evil CEOs
Perhaps the most obvious contender for the crown is Roxxon, Marvel's default uncaring company. Under the stewardship of Dario Agger, Roxxon engaged in gamma fracking and human experimentation, empowered the alien tyrant Xemnu to brainwash the world, and even sided against humanity in The War of the Realms, aiding the Dark Elf Malekith in his takeover of Earth while plundering other realms for their natural resources. But that's the thing - while Roxxon isn't a moral company, it's only ever as bad as the person behind the wheel. Roxxon's crimes should have gotten the company shut down, but ultimately they were the work of Agger taking singular control and intimidating his staff. Roxxon is a force for evil to be sure, but there's plenty worse out there.
For this reason, similar organizations like Oscorp and Hammer Industries don't quite make the grade either. Sure, they're used for evil, but in the wild world of comics, there are organizations which are far worse. Alchemax is more of a contender, given that it exists in a future where companies have more power over the populace and corruption runs through the entirety of the organization. Best known as one of the central antagonists of Marvel's 2099 timeline, Alchemax does exist in mainstream Marvel comics, run in the present day by Spider-Man's old flame Liz Allen. But despite its dark deeds in the year 2099, such as helping the evil Hulk Maestro take over the world, Alchemax isn't as bad as it gets.
Another notable contender is AIM. While many of Marvel's evil organizations are technically incorporated, AIM is the one that actually behaved like a business at one point (a step down from its previous claim to being a full-fledged country in Nick Spencer, Ed Brisson, Jackson Butch Guice, and Luke Ross' Secret Avengers.) AIM's mission statement is specifically to practice extreme science without moral restriction, making them just a little bit more dastardly than a company which might have some restraint under better leadership. Unfortunately for their ranking here (though fortunately for the world), acting like a company showed that even AIM could be used for good when New Mutants hero Sunspot, aka Roberto da Costa, bought a controlling interest and turned them into support for the Avengers. While a chunk of AIM split off after da Costa took control, many were happy to stay on, suggesting again that AIM's misdeeds are tied more to its leadership than its core values.
Marvel's Worst Companies
While the potential for good doesn't stop these companies from being evil in practice, it does prevent them from being the most evil when there are some truly irredeemable organizations out there. On that basis, the only real contenders for Marvel's most evil company are the Beyond Corporation and Hexus. The Beyond Corporation is certainly evil through and through - not actually an Earthly corporation, but rather the metaphysical expression of one or more Beyonders - powerful beings from outside reality who like to play with Earth's heroes. The Beyond Corporation is inherently evil, concerned only with enacting its masters' whims on the Earthly plane, but it's also only technically a corporation - it's an evil business in the same way that if X-Men villain Mystique briefly shapeshifted into a horse, she'd be Marvel's most evil horse. While the Beyond Corporation's appearances in Captain America and the Mighty Avengers showed how dangerous it could be, it's more an extra-dimensional being pretending to be a corporation than a true business.
That leaves Hexus, aka Brand Hex, as the potential winner. Hexus was introduced in Grant Morrison and artist J.G. Jones' Marvel Boy. The titular hero, aka Noh-Varr, was part of an exploratory team sent by the Kree race of an alternate reality. Marvel Boy explored countless realities with his team, taking samples and spreading the Kree gospel as he went, before crash-landing on Earth and becoming a prisoner of the Midas Corporation (a pretty nasty outfit in its own right, though again one where the driving force behind the evil was a single individual.) Sadly, this resulted in Hexus - one of the samples/prisoners the team had taken on their travels - getting free.
It turned out that Hexus was a living corporation which "employed" humans to do its bidding, forcing them to work to spread Brand Hex to every corner of the world and create a financial, cultural, and spiritual monopoly. Every human employed by Hexus became part of its hivemind, and it had a tendency to channel their body heat through their eyes to kill its immediate enemies, not caring about the "employee turnover" that resulted. Hexus' ultimate aim was to take over the planet and then spread, conquering world after world with weaponized business practices, and Marvel Boy was only able to defeat it by hacking its secrets and sharing them with Earth's "native" corporations, allowing Hexus' natural predators to tear it to pieces. Thanos may have wanted to wipe out half of all life, but he never intended to enslave all life, forever, wiping out free will and setting every living being to constant work serving his ultimately pointless whims. Since Hexus is a corporation in the truest sense - albeit an alien version with its own consciousness - and because every single employee is equally involved in its nefarious plans, and would carry on its mission given the chance, it's more than worthy of the title of Marvel's most evil company, despite some stiff competition.