Payment processing companies (of the traditional variety; I'm not sure about the newbies like Stripe) also require a list of the company's principals with their social security numbers when you open a merchant account. The purpose of that is to add those individuals to TMF/MATCH if the account is closed for some kind of abuse, like excessive fraud. Other banks check those lists before opening a new payment processing account, which theoretically stops you from using shell companies to perpetuate credit card fraud after termination.