In his book Young Stalin, Sebag-Monterfiore gives numerous details of how in 1901 the Rothschilds employed Stalin in their oil refinery in Batumi, how there is evidence he "was henceforth in secret contact with the Rothschilds mangagement - the start of his murky but lucrative relationship with the oil barons", and how the Rothschilds financed the Bolsheviks. Which is all pretty remarkable!
Simon Sebag-Monterfiore is himself related, although fairly distantly, to the Rothschild family. He and Nathaniel Philip Rothschild are both great-great-great-great-great-grandsons of Levi Barent-Cohen, the great-great uncle of Karl Marx. Below is a family tree for the Sebag-Montefiores I've knocked-up, showing their connections to the Barent-Cohen and Rothschild families. A more complete, but far older family tree of the Cohen and Montefiore "pedigree" can be viewed in this 1919 book penned by one of the clan.
But later admits in a footnote (sometimes referred to as "hiding"):"It remains astonishing how the Rothschilds and other oil barons, among the richest tycoons in Europe, funded the Bolsheviks, who would ultimately destroy their interests." (p.159)
So the Rothschilds sold their interests in Russia five years before the Bolsheviks (who they funded) seized power."In 1912, Eduard de Rothschild, Alphonse’s son, sold most of the Rothschild interests in Baku to Royal Dutch Shell, then headed by Henri Deterding. The Rothschilds took most of their payment in Royal Dutch Shell shares. This proved a classically brilliant Rothschild deal. The Rothschilds eschewed oil investments in Russia for almost a century- making another fortune in the Russian oil boom of the twenty-first century." (p.344)