How Does the Threat of a 51% Attack Influence the Decision to List a New Altcoin on an Exchange?

Exchanges consider the threat of a 51% attack a major risk when deciding to list a new altcoin, particularly a low-hash-rate PoW coin. If the coin is easily attackable, the exchange faces the risk of double-spend fraud, where an attacker deposits coins, trades them for another asset, and then reverses the deposit transaction.

To mitigate this, exchanges often require a high number of confirmations for deposits of such coins, or they may simply refuse to list them.