Call it a “buyer strike” or “self-sanctioning,” but Russian crude is shunned in the physical market, even as a barrel battle pushes oil futures to their highest levels in years.

“The current central bank sanctions and selective SWIFT measures are leading to major risk aversion among key market participants,” said Helima Croft, head of global commodities strategy at RBC Capital Markets, in a note on Thursday.

The US and its allies have…