>>8333800 Billionaire. Britain. Tax Evasion. Made me think of the Clintons. Under this spelling "Tinkov", nothing came up in the DoS FOIA reading room. However, Spelling it "Tinkoff" netted a single document from 2010 - asking if WJC could meet w/a list of Russian businessmen.
https://foia.state.gov/Search/results.aspx?searchText=%22tinkoff%22&beginDate=&endDate=&publishedBeginDate=&publishedEndDate=&caseNumber=