Currently, Ethereum is the second largest cryptocurrency by market cap with a market cap at the time of this writing of 200 billion.
For reference, Bitcoin has a market cap of just under 1 trillion. Additionally, the closest market cap under Ethereum is a handful of coins in the 30 billion area. It’s safe to say Ethereum is safely in second place.
Many speculate that at some Bitcoin will no longer be the largest coin in the world and if any coin can dethrone it, Ethereum seems the likely candidate.