In the UK if an individual gets paid with a loan, then have to repay it within a tax year or otherwise pay tax on it as if it was regular income (disguised remuneration). This has actually been applied retrospectively and drove many people to bankruptcy.
Why this cannot be applied to transfers between companies if they are related?
I’m not sure what you mean. Transfer pricing does happen within a tax year.
A gizmo is 95% assembled in Country A with 50% tax rate. Company wants to sell that 95% gizmo for 10% of the actual price to their subsidiary in Country B with a 5% tax rate. Finish the product there then book 90% of the revenue in the low tax country.
That’s transfer pricing. There are account regulations that define how that price is set. That said it’s hard with IP and other assets with less tangible value.
Why this cannot be applied to transfers between companies if they are related?