Because you need substantial income flows (B2B or B2C sales), preferably not all coming from the same jurisdiction. And a reason to do something ("economic subs

Because you need substantial income flows (B2B or B2C sales), preferably not all coming from the same jurisdiction. And a reason to do something ("economic substance", i.e. come up with a good story why you need to route that money through the BVI). Every situation is different, and offers different opportunities. Technology companies can use different techniques when compared to a retailer. Some "loopholes" have genuine reasons to exist and are hard to fix. Something as simple as corporate interest deduction comes to mind, which can be used to help grow a business through debt financing (the way most companies use it). However, if you set it up properly, it can also be used to strip earnings away to a different jurisdiction. But whether you want to use this technique depends on how your corporate structure is set up and capitalised. What works for an american company might not work for a UK company, for example. Think of building an extremely complex custom system (where if you mess it up, you get a huge bill a few years down the line); that's essentially what tax optimisation is at the multinational level.