When two companies in the same corporate family do business across borders, they do more than ship goods. They share services, use each other’s patents, and split the cost of developing new technology. These inside deals can shift profits and tax bills in subtle ways. This chapter walks you through the special rules that keep the pricing of services and intangibles fair. You’ll also see what a multinational group must do to document its prices, avoid penalties, and settle disagreements with tax officials.