Federal law still treats cannabis as an illegal substance, and traditional banks have been wary of getting involved. Wealthy financiers have moved in to fill the void — including a growing cast of investors from Russia and former Soviet Union countries who have helped shape the industry's growth. One of the nation’s largest cannabis companies, Curaleaf, is led by one of Russia’s most influential financiers and backed by another, allowing the company to pursue rapid expansion and hefty acquisitions. Investment firms have taken their own stakes: A San Francisco-based venture capital fund run by the Russian tech entrepreneur Pavel Cherkashin, backed largely by investors from Russia and the former Soviet Union, has put $2 million into Pure Spectrum, a Colorado-based business marketing CBD products.