The Guardian is reporting that the fifth richest man in Russia claims he no longer has his billions, so he can't be sanctioned.
According to a spokesperson for Alisher Usmanov, the assets are in irrevocable trusts, so they don't actually belong to him, and thus can't be sanctioned.
One of the ways that the wealthiest Russians have been able to skirt any accountability is by putting their assets into shell companies, trusts and other dodges. In the case of Usmanov, his UK properties and a superyacht are untouchable because of a technicality. Such Trusts can't be changed in any way after they've been signed and notarized.
"From that point on, Mr. Usmanov did not own them, nor was he able to manage them or deal with their sale, but could only use them on a rental basis," the spokesperson told the Guardian. "Mr. Usmanov withdrew from the beneficiaries of the trusts, donating his beneficial rights to his family."
If his beneficiaries are Russian, they would also fall under the sanctions, but because the assets are in the trust, it's unclear if the UK could make that link to trigger the seized assets.
"All of Mr. Usmanov's properties were settled into the irrevocable trusts long before the sanctions came," said spokesperson when asked by Reuters. "It had nothing to do with sanctions and was determined by estate planning."
The International Consortium of Investigative Journalists reported in 2016 about the so-called Panama Papers, a cache of information detailing the way the wealthy of the world stash their cash and assets through shell companies, LLCs and trusts. In a specific part about the Russian oligarchs, the ICIJ revealed that the financial deals ultimately ensure money can also be channeled to "a network of people and companies linked to President Vladimir Putin."