Saudi Arabia led the cartel by pledging its own 500,000 barrel-a-day supply reduction. Fellow members including Kuwait, the United Arabia Emirates and Algeria followed suit, while Russia said the production cut it was implementing from March to June would continue until the end of the 2023. 

That adds up to a production cut of about 1.1 million barrels a day starting next month, a significant reduction for a market where — despite the recent price fluctuations — supply was looking tight for the latter part of the year. 

Oil fell to a 15-month low last month due to the turmoil caused by the collapse of Silicon Valley bank and the rescue of Credit Suisse AG. Prices had recovered the worst of those losses as the banking crisis showed signs of stabilizing, with Brent crude closing just below $80 a barrel on Friday, up 14% from its March trough.

As recently as Friday, delegates from the Organization of Petroleum Exporting Countries and its allies had been indicating privately that there was no intention to change their production limits. 

All fourteen traders and analysts polled last week by Bloomberg predicted no change. They were taking their lead from Saudi Energy Minister Prince Abdulaziz bin Salman, who had said last month that the current OPEC+ production targets are “here to stay for the rest of the year, period.” 

–With assistance from Fiona MacDonald, Khalid Al-Ansary and Omar Tamo.