• Market share: If one firm starts to gain a significant amount of market share, the other firms may try to defend their market share by lowering prices.
• New entrant: If a new firm enters the market, the existing firms may respond by lowering prices to try to maintain their market share.
• Changing economic conditions: If there is an economic downturn, firms may try to stimulate demand by lowering prices.
• Strategic moves: A firm may intentionally lower prices to put pressure on its competitors and force them to lower their prices as well.

Price wars can be risky because they can lead to lower profits for all firms involved and can be difficult to control once they start.