The "alternative" crypto coin is up around 240% this year, while the world's best-known cryptocurrency is up less than 38%.
It's been a volatile few months in the crypto world, with bitcoin's value peaking in April at around $65,000 before falling back to around $30,000, while ether peaked in May at around $4,000 and is now trading around $2,500.
Ether is viewed as an alternative to bitcoin. Fans like it for a number of reasons including the fact it underpins many other cryptocurrencies, but it's yet to be adopted by private institutions in the way that bitcoin has been.
It's important to note that ether's market cap is less than half that of bitcoin's, but trading volumes for the smaller coin surged to $600 billion in May — 60% higher than bitcoin volumes, according to Morgan Stanley.
There are some key reasons for the outperformance of ether, according to the investment bank, which updated its views on crypto in a note last week.