A cartel is a group of independent market participants who collude with each other in order to improve their profits and dominate the market. A cartel is an organization formed by producers to limit competition and increase prices by creating artificial shortages through low production quotas, stockpiling, and marketing quotas. Cartels can be vertical or horizontal but are inherently unstable due to the temptation to defect and falling prices for all members. Additionally, advancements in technology or the emergence of substitutes may undermine cartel pricing power, leading to the breakdown of the cooperation needed to sustain the cartel. Cartels are usually associations in the same sphere of business, and thus an alliance of rivals. Most jurisdictions consider it anti-competitive behavior and have outlawed such practices. Cartel behavior includes price fixing, bid rigging, and reductions in output. The doctrine in economics that analyzes cartels is cartel theory. Cartels are distinguished from other forms of collusion or anti-competitive organization such as corporate mergers.