In many cases, none because they'll just keep pirating yours. Even if the company has a "don't pirate, we want to pay for it" policy, some employees will still do it! That's something to keep in mind. For some, piracy has become the default way to get software.
You need to make it easier to buy than to pirate. I believe taking small credit card payments for 1-seat licenses is key here. If a low-ranking employee's options are piracy vs. informally asking their manager "hey can I buy this $99 software" and entering their credit card, you're much more likely to make a sale than if the employee has to choose between piracy and dealing with their purchasing department, legal department, IT security, etc.
This only applies to companies with corporate credit cards and employees that have a lot of flexibility, of course. I don't know what other methods you need to offer to make it easy for other companies.
Usually, the "main" users had a valid license, but there were cracks floating around for the people that used the software a couple times a year. We're talking a about stuff costing thousands here. This was, if not approved, certainly turned a blind eye by management.