Moscow rules

The fate of the relationship with Russia will be critical as balances tighten and competitor output builds

Saudi Arabia's new-found diplomatic bond with Russia will remain at the core of Opec's efforts to drain oil stocks in 2018. Cuts will likely be extended again, possibly to the end of the year, as non-Opec supply out-strips demand growth, reducing the need for the group's own oil. Saudi Arabia and Russia together account for more than 20% of global supply and are both titans of the oil-exporting world. Crucially, both also have either spare capacity or a proven ability to expand oil production in the medium term. So their joint determination to see through the output cuts agreed in late 2016 should be taken seriously. The partnership appeared tentative early on. But following King Salman's au