Earlier quoted context omitted.
They wouldn't get to deduct the costs of importing those raw materials, but they would get to deduct the costs (labour, probably) of refining them and making something out of those raw materials. And if they sell back to the country they imported raw materials from, they get to deduct the raw material costs from those profits (assuming that country uses a similar scheme). But you're right, for a company that makes th…
That's totally unworkable. That banana you buy in the supermarket is imported and sold with a gross margin in the low single-digits. Taxes the revenue at income tax levels would effectively raise prices by the tax rate, i. e. 30% or so. If the supermarket doesn't buy the banana directly from the plantation, that tax would accrue at every step of the chain . You'd effectively be prohibiting trade and people would swit…
But it's true, local products would have a significant fiscal advantage over products from other countries, especially products with complicated supply chains across many different countries, some of which countries are tax havens that the target country doesn't consider having a fair tax system.
The change would probably be a shock to many companies, but it'd also make it impossible for companies to shift their profits to tax havens.