Coinbase Institutional: Altcoin Season Could Begin in September as Bitcoin’s Market Share Erodes

In its August market outlook, published on Aug. 14, Coinbase’s global head of research David Duong identified three key factors that could trigger what traders call “altcoin season” — a period when non-bitcoin cryptocurrencies, often led by Ethereum (ETH), Solana (SOL), and other large-cap tokens, deliver higher percentage gains than bitcoin over an extended timeframe.

Enter the alt szn, source: Coinbase

Declining Bitcoin Dominance
Bitcoin’s share of total crypto market capitalization has eased after peaking earlier this year. According to Coinbase, historical trends suggest that when bitcoin dominance falls, capital tends to flow first into large-cap altcoins before rotating into mid- and small-cap tokens. The firm anticipates this rotation effect could accelerate in September.

Liquidity Conditions Improving
Coinbase also pointed to stronger liquidity across major exchanges, including narrower bid-ask spreads and deeper order books for leading altcoins. This environment, the report says, makes it easier for institutional and large-scale traders to execute sizable transactions without incurring significant price slippage, encouraging broader participation in non-bitcoin markets.

Growing Risk Appetite
The third driver is sentiment. With macroeconomic conditions stabilizing and crypto market volatility contained, Coinbase believes investors are increasingly willing to take on more risk in pursuit of higher returns. If bitcoin’s price consolidates rather than reaching new highs, that capital could flow into higher-beta assets, potentially extending the altcoin rally through year-end.

While the report does not name specific tokens expected to lead the move, it highlights patterns from previous cycles where top-tier altcoins outperformed first, followed by smaller, more speculative assets. Coinbase also noted that the scale and duration of the trend will depend on market conditions and broader economic factors.

Year-to-date, Bitcoin has gained 27.2%, trailing ETH (+37.9%) and XRP (+49%). Other altcoins have seen mixed performance, with SOL up 1.67%, ADA up 8.96%, and DOGE down 27.5%. Coinbase maintains that conditions in the months ahead could favor a broad rotation into altcoins.