What is the most common form of collusion?

The most common form of collusion is price-fixing, where competing companies agree to set prices at a certain level rather than letting market forces dictate them. This practice undermines competition, leading to higher prices for consumers and reduced market efficiency. Price-fixing can occur in various industries and is illegal in many jurisdictions due to its harmful effects on the economy. Other forms of collusion may include market allocation and bid-rigging, but price-fixing remains the most prevalent.