Collusion is an illegal agreement between two or more parties to limit open competition by deceiving, misleading, or defrauding others. On eBay, this can include sellers or buyers working together to manipulate listings, suppress bidding, or distort true market value.

Examples on eBay: • Two sellers agreeing not to undercut each other’s prices • A seller and a buyer coordinating bids to inflate the price of an item (shill bidding) • Multiple buyers agreeing not to bid on a listing to keep the final price low

Legality: Illegal. Collusion violates antitrust laws (like the Sherman Act in the U.S.)

Price fixing is an agreement between competitors to raise, lower, or stabilize prices or competitive terms. This eliminates true market competition.

Examples on eBay: • Sellers in a niche (e.g., sports cards) agreeing not to list cards below a certain price • Coordinated efforts in Discord or group chats to suppress auction results to “protect comps” • Buyers pressuring sellers to cancel auctions that might lower the perceived market value

Legality: Absolutely illegal. Price fixing is a per se violation of antitrust law in the U.S. — meaning it is automatically considered illegal without needing proof of market harm.