Oil prices have surged after oil producing countries that are not Opec members agreed to cut output.
Brent crude jumped to $57.89 a barrel – the highest since July 2015 – before falling back to $56.79, although that was still a gain of 4.5% on the day.
The new deal is the first global pact in 15 years.
“Once cuts are implemented at the start of 2017, oil markets will shift from surplus into deficit,” said analysts at AB Bernstein.
Brent oil price
But some expressed doubts about the deal’s long-term impact on prices.
Thomas Moore, investment director at Standard Life Investments, told BBC Radio 5 live: “You will see the oil price jump this morning – that’s understandable – but I think you need to put it in context.
“This is a cut of 550,000 barrels a day, and of course we have had about a million off Opec’s production.
“But if you think about overall world production, Opec’s producing 33 million barrels per day, so those numbers of 1.5 million are good, but they are not that good.
“And Opec accounts for only about 40% of world crude production, so yes, there’s a day-one impact, but I think it’s at the edges here.”
Those taking part in Saturday’s deal included Russia – which will provide the lion’s share of the cut – as well as Mexico and Bahrain among others.
It comes after more than two years of depressed oil prices, which have more than halved since 2014 due to a supply glut on the market.