Dr. Tom McDonnell:

That is correct. If you are using transfer pricing and you are selling to yourself, you just decide to sell for a lower rate. This means the amount affected by the tariff is commensurately less. However, let us say you are in Ireland and you have your price set at a high level because you have a low corporation tax rate here and you are selling to country B so that the profits are made in Ireland. If a tariff is imposed, it may end that rationale or it may end it being cheaper to assign the massive profit to Ireland. They are therefore incentivised to change the price and charge a lower price to their sister company in the US, or wherever it might be, because they are worried that the tariff costs will be lower than the savings on the corporation tax side.