Former Soviet Union (FSU). For the whole group, the supply curve goes from the origin (0,0) through the observed point (P, Q). Assuming price equals marginal cost, diminishing returns require an upward slope. The curve is summed up in the slope coefficient b. Thus if P = bQ, then b = P/Q. (Source: OPEC, March 2018) How Tight Is The Market For Oil? As before, OPEC's report implies a price-favorable outlook for the supply/demand balance for crude oil in 2018. Global oil supply will outpace demand throughout 2019, the International Energy Agency forecasted in its latest Oil Market Report. Since midyear, oil supply had increased sharply with gains in the Middle East, Russia, and the US more than compensating for falls in production in Iran, Venezuela, and elsewhere, IEA said.