How Does the Cost of a 51% Attack Change with the Coin’s Market Capitalization?

The cost of a 51% attack is generally inversely proportional to the coin's market capitalization and its hash rate. For PoW, a higher market cap coin usually attracts more legitimate miners, driving up the hash rate and thus the cost to rent 51% of that hash rate.

For PoS, a higher market cap means the cost to acquire 51% of the coin supply for staking is significantly higher, making the attack economically infeasible for larger coins.