One notable example—after a 92% surge in August 2017, ETH fell 21% in September. Similar patterns appeared in later cycles, including 2021.
$ETH seasonality in September during post-halving years is typically negative.
— CryptoGoos (@crypto_goos) August 22, 2025
Will this time be different? pic.twitter.com/h9hJ40V3np
That backdrop contrasts with the latest run-up. From early August, Ether has climbed about 25% and set a new all-time high, eclipsing the prior peak near $4,867 (per CoinGecko).
Could 2025 break the script? Some market participants think so, pointing to fresh institutional demand. Over the past month, spot Ethereum ETFs have attracted roughly $2.79 billion in net inflows, while Bitcoin ETFs saw about $1.2 billion in outflows (SoSoValue).
Сorporate treasuries have also been building positions—an estimated 4.1 million ETH, valued around $18.7 billion, are now held on balance sheets. BitMine Immersion Tech leads public companies with more than 1.5 million ETH worth approximately $6.9 billion (Strategic ETH Reserve). Combined with ETF holdings, institutions and corporates are estimated to control close to 9% of total ETH supply.
Adding to the rotation narrative, several Bitcoin “whales” have reportedly lightened BTC exposure to increase stakes in Ethereum during the latest rally. Whether that institutional bid can overpower ETH’s usual September drag is what traders will be watching next
Earlier, FORECK.INFO reported on Ethereum’s rally toward $5,000 and the factors driving investor demand for the asset.