The two offshore zones, known as special administrative regions, or SARs, used tax incentives to entice Russian companies based in other countries to move to Russia.
Located in the far western and eastern reaches of the country–one on Oktyabrsky Island in the Kaliningrad area sandwiched between Lithuania and Poland, the other on Russky Island near the borders with China and North Korea–the two special regions gave oligarchs an exit ramp from foreign jurisdictions where they could be subject to sanctions.
There are plenty of areas in the US where crooks and billionaires can hide money as well. It is an international shell game.