As good as it gets for Opec

Compliance with the Opec deal is defying the group's sceptics. How long can it last?

Opec's supply deal is off to a flyer. Compliance among the members that agreed to cut production is more than 90%. Brent, trading above $55 a barrel in mid-February, is about 14% above its price just before the group's meeting at the end of November 2016. But keep the champagne on ice. January's level of compliance will probably be the high-water mark of this Opec agreement. Discipline fades over time. The more successful the cuts are in raising the price, the greater the temptation for members to cheat their quotas. And the biggest producers stand ready to react when the deal unravels. Compliance is uneven. Saudi Arabia has slashed almost 0.5m barrels a day, according to Opec's secondary so