Bitcoin dominance has fallen to a six-month low while altcoin market cap jumped 50% since July, setting the stage for a potential September altseason, said Coinbase.
Altcoins have seen significant growth recently, and current crypto market conditions suggest there could soon be a shift towards cryptocurrencies outside of Bitcoin, according to Coinbase.
“We think current market conditions now suggest a potential shift towards a full-scale altcoin season as we approach September,” Coinbase Institutional’s global head of research, David Duong, wrote in a monthly outlook report on Thursday.
The Coinbase analyst joins a growing chorus of traders and market observers tipping for an imminent altcoin season.
The firm defines altcoin season as when at least 75% of the top 50 altcoins by market capitalization outperform Bitcoin (BTC) over the preceding 90 days.
Duong added that there was “significant retail capital sitting on the sidelines” in money market funds, and Federal Reserve easing could “unlock greater retail participation in the medium term.”
July’s US Consumer Price Index (CPI) this week showed inflation holding at 2.7% year-over-year, which has seen the odds of a Fed September rate cut increase to 92% on futures markets.
A lower interest rate environment potentially draws fresh capital into the market and could be a catalyst for high-risk assets such as altcoins.
Another factor influencing the arrival of altseason is the decline in Bitcoin dominance or total crypto market capitalization share.
Bitcoin’s market dominance has declined around 10% from over 65% in May 2025 to approximately 59% by August 2025, “signaling the early stages of capital rotation into altcoins,” Duong wrote.
Related: Altseason on horizon amid liquidity surge, regulatory clarity: Sygnum
Bitcoin dominance is currently 59.5%, around its lowest level since late January, according to TradingView.
“Bitcoin dominance has just formed its first monthly bearish cross since January 2021,” observed crypto day trader Ito Shimotsuma on Thursday. “Back then, altcoins went up only for four months when it happened,” he said before adding, “Something similar this time will cause an up-only rally till December 2025.”
Altcoin season indexes have also been climbing higher, but still remain well below the 75 threshold by which they historically define altseasons, even though the altcoin market cap has climbed over 50% since early July, Duong observed.
CoinMarketCapʼs Altcoin Season Index currently sits at 44, having climbed from below 25 in July. Blockchain Center’s Altcoin Season Index is a neutral 53, while CryptoRank’s Altseason Index is a level 50.
Duong said that current momentum is being fueled by digital asset treasuries and stablecoin narratives, with the divergence in altseason indexes and total altcoin market cap “reflecting rising institutional interest in Ethereum,” before concluding:
“With the altcoin market cap climbing and the Altcoin Season Index showing early positive signals, we believe conditions are setting up for a potential rotation into a more mature altcoin season as we head into September.”
“Three key conditions need to align for an altcoin season to take hold: a supportive macro backdrop, declining BTC dominance, and a strong new narrative,” Joanna Liang, founding partner of Singapore-based venture capital firm Jsquare, told Cointelegraph.
“Past cycles were driven by clear catalysts: ICOs in 2017-2018, Layer-1s in 2018-2019, and DeFi/NFTs in 2021-2022,” she said before adding:
“In this cycle, the market is still waiting for a compelling primary-market signal that can draw significant new capital and truly ignite an altseason.”
