Backdated paperwork hid Abramovich's yachts and mansions from tax, and sanctions enforcers should worry.

The BBC found backdated paperwork that made Abramovich's yachts and mansions disappear from his accounts, and why that matters for enforcement.

Leaked corporate records point to a long-running paper trail that helped the Russian billionaire's businesses dodge tax and hide assets, and they put a Big Four firm in the frame.