A multi-layered approach would definitely be best. Can I ask what you have done already?
Cursing the ground under its headquarters would be a good idea. I would be targeting the people within the business to fight amongst themselves, possibly also to make any of them give in to any negative urges, like stealing or cheating, and also for their crimes to be discovered. Also for them to turn on each other, so if any of them have committed a crime, their coworkers will rat them out. Cause them to make stupid choices like firing their best staff, making paycuts, or making their best workers redundant… things like that.
Some corporative logos are actually sigils. Spare type. So you should have that in mind while casting. The whole concept is that they won’t go away because they’re taken from the collective unconscious or whatever it is called in English. They were here before us. So in your place I would start there.
With what you’ve already done, I would consider inviting parasites into the company and the grounds, rather than adding more specific names. Companies are usually run (daily) by those regular folk we don’t know about. To cause more mistakes on a daily basis, I would call up an entity you trust and ask them to gather parasites to the grounds, buildings. It’ll spread out the damage to more areas.