What';s a CR4?
"CR4" stands for "Concentration Ratio of the top 4 firms." Each corporation in a sector has a "market share" - the amount of the market that that corporation controls. For instance, Cargill's market share of the Canadian beef packing system will be nearly 50% following its takeover of Better Beef and the expansion of Cargill's Alberta plant.
The CR4 is calculated by adding up the market shares of the biggest 4 players. For instance, the four biggest players in the Canadian nitrogen fertilizer sector are Agrium, Saskferco (partly owned by Cargill), Canadian Fertilizers Ltd, (a joint venture of various co-ops and corporations), and Simplot Canada. The CR4 for the secotr is 81.3%.
A generations ago, economists said that markets would have insufficient competition of the CR4 rose above 40%.