September is approaching, and Ethereum speculators are worried, as the ninth month of the year is often associated with weakness in this second-largest cryptocurrency. With an average loss of -6.42% since 2016, September is the worst-performing month for Ethereum in most cycles.

Ethereum Has Grown Strongly Thanks to Institutional Push

Ethereum has recently made significant strides, nearing its all-time high and breathing new life into the ETH community as well as many other cryptocurrencies. As of mid-August 2025, ETH is trading above $4,700, up about 76% since the beginning of the year and about 25% just from the start of August, marking the best price performance since the bull run of 2021.

Institutional capital flows are the main driving force behind Ethereum's price surge, as spot ETH ETFs attracted nearly $3 billion in net capital flows throughout August, pushing prices higher and revealing a new trend among buyers who are institutions.

Corporate treasury adoption is also skyrocketing, with companies collectively accumulating more than $17 billion in ETH reserves just this year, locking up supply and boosting upward price momentum.

Co-founder of Fundstrat and now chairman of BitMINE Immersion Technologies, Tom Lee has become a focal point this year with his company's pivot towards Ethereum.

Just over a month later, BitMINE has accumulated the world's largest corporate Ethereum treasury, boasting over $6.6 billion in ETH to become the largest ETH holder, surpassing even major investment and tech firms like ConsenSys.

Macroeconomic conditions remain favorable as the dovish signals from the U.S. Federal Reserve and improved global risk sentiment have contributed to deeper institutional interest.

On-chain factors like DeFi activity and protocol upgrades such as Pectra have further reduced liquidity supply and encouraged long-term holding, creating strong momentum for ETH's price performance.

Has the notorious September weakness of ETH come to an end?

However, as September approaches, portfolio rebalancing after strong summer rallies, along with tax-related sell-offs, could help cool off the summer heat. Bitcoin and cryptocurrency trader Crypto Rover has questioned the peculiar seasonality of Ethereum, posting:

“SEPTEMBER IS USUALLY A DISCOUNT MONTH FOR $ETH

Not just in general, but particularly in the years following the halving.
2017: -21.65%
2021: -12.55%
2025: ???
What is your prediction?”

ETH's price history shows a persistent and often harsh September pattern. Since 2016, ETH's gains in August are typically wiped out in September. In 2017, ETH rose 92% in August, then fell -21.65% in September, after China announced a ban on ICOs.

In 2020, ETH's price surged about 25%, then fell 17% in September, and in August 2021, ETH's price rose about 35% before dropping 12% in September.

Not Everyone is Pessimistic About ETH

Despite this clear trend, not all analysts are pessimistic. Standard Chartered Bank recently forecasted that ETH prices will reach $7,500 by the end of 2025, with a long-term target of $12,000 in 2026 and $18,000 in 2027.

On August 13, 2025, Tom Lee told CNBC that he expects Ethereum to "continue to accelerate" with growth momentum driven by ETF capital flows and institutional adoption, pushing the price above $7,000 per coin.

Although data suggests that ETH will face seasonal difficulties in September, especially after a strong growth month in August, if ETH can break free from the September curse, a bullish fourth quarter awaits.