It's complicated. "Money they made in their country" is hard to define. Large companies abuse intangible assets to shift profits around, but it's hard to say at what point abuse starts. For example, Google USA sells advertising to its clients. But, the assets it is selling are actually owned by Google Ireland. Google Ireland charges Google USA a license fee of 100% of the revenue they made. Suddenly, Google USA has net profit of 0 and Google Ireland has a large net profit.
This at the same time happens frequently, but also some amount of intercompany shifts in profit are reasonable. Google Ireland might be the actual owner of the asset. Company ownership might be fuzzy as well - maybe foreign subsidiary is only partially owned by the parent and partially owned by another company. Drawing the line can be very hard. Do we make it so companies are not allowed to sell or transfer assets overseas?
Probably the best solution is a minimum tax worldwide. This reduces the incentives to shift profits around, since the tax rates are the same everywhere.
This at the same time happens frequently, but also some amount of intercompany shifts in profit are reasonable. Google Ireland might be the actual owner of the asset. Company ownership might be fuzzy as well - maybe foreign subsidiary is only partially owned by the parent and partially owned by another company. Drawing the line can be very hard. Do we make it so companies are not allowed to sell or transfer assets overseas?
Probably the best solution is a minimum tax worldwide. This reduces the incentives to shift profits around, since the tax rates are the same everywhere.