Over the medium term, many will limit output.

Together they have had an agreement to limit output to maintain the level of oil prices.

When the cartel and 11 non-members agreed to limit output by 1.8m barrels a day (mbd), the nonmembers agreed to cut their output by 600,000 barrels daily.

These agreements could be to limit output, collusively share information, fix prices, tender collectively and share markets out.

A monopoly occurs when a firm supplies the total output in the market; the firm can therefore limit output and raise prices because it has no fear of competition.