Ethereum (ETH) outperformed Bitcoin (BTC) in the third quarter of 2025 as investors shifted capital towards altcoins, DeFi protocols, and tokenized assets. The cryptocurrency market added over $500 billion in value, with Ethereum and other large-cap tokens leading the charge. While Bitcoin initially led the market in July, its momentum waned by September, allowing Ethereum to reach a new all-time high. The period also saw increased interest in meme coins, stablecoins, and DeFi, contributing to a decline in Bitcoin's market dominance.