Altseason Index 2025: A Complete Guide for Crypto Investors | Forecast & Analysis

Altseason Index: A Complete Guide for the Crypto Investor

 

Date: September 11, 2025

 

What is the Altseason Index and how does it work?

 

The Altseason Index is a specialized tool that measures how much altcoins (all cryptocurrencies except Bitcoin) are outperforming BTC in terms of returns. When the index exceeds a value of 75, it is generally accepted that a full-fledged “altseason” has begun—a period when most altcoins are growing faster than Bitcoin.

 

Historically, the index was developed to help investors identify market cycles. It is calculated based on several key factors. The primary method involves analyzing the price dynamics of the top 50 altcoins over the last 90 days and comparing them to Bitcoin’s returns. If 75% or more altcoins show better performance than BTC, it signals the start of an altseason.

 

Some versions of the index also include analysis of social media sentiment, blockchain analytics data, and technical indicators for a more comprehensive market picture.

 

Current market situation (September 11, 2025)

 

As of today, the total cryptocurrency market capitalization is showing positive dynamics. The Bitcoin price has reached $114,144, setting a new September high, while Ethereum is trading around $4,414, showing a 2.7% increase over 24 hours.

 

The Altseason Index is currently showing a value of around 32-33 (according to summer 2025 data), indicating a gradual approach towards the altseason threshold, but not its start yet. Bitcoin dominance remains at around 60%, confirming that the market is still in the “Bitcoin season” phase.

 

Historical examples and cycles

 

Throughout the entire history of the crypto market, there have been only two full-fledged altseasons:

 

The first altseason (2017-2018) lasted 310 days, during which the altcoin market capitalization grew by $470 billion (a 56,425% increase). Bitcoin dominance fell from ~96% to ~36%.

 

The second altseason (2021) lasted 309 days and brought a growth in altcoin market capitalization of $1.5 trillion (a 650% increase). The peak value of altcoins coincided with Bitcoin’s all-time high in November 2021.

 

Interestingly, both altseasons lasted almost the same amount of time—310 and 309 days respectively, indicating a possible cyclicity of this phenomenon.

 

The current bear cycle in the altcoin market has already lasted more than 1200 days, making it the longest in history. The sector’s capitalization is still 40% below its previous peak, creating potential opportunities for growth.

 

Can the Altseason Index be manipulated?

 

Theoretically, manipulation of the Altseason Index is possible but difficult for several reasons. Firstly, the index is calculated based on information from multiple exchanges and sources, which provides a certain degree of data decentralization. Secondly, the calculation takes into account various metrics, which complicates manipulation. Furthermore, the calculation methodology is usually open and transparent.

 

However, it is worth noting that large players (whales) can influence individual components of the index, for example, by artificially inflating trading volumes of certain altcoins or manipulating their prices. Therefore, one should not blindly trust the index—it is important to analyze the market situation comprehensively.

 

How to use the Altseason Index correctly in trading

 

The Altseason Index is a useful tool, but not a panacea. Here is how to use it correctly:

 

Do not blindly follow the index values. A value above 75% does not always mean you need to urgently buy all altcoins. Historically, there have been cases where the index reached peak values just before a market correction.

 

Combine it with other indicators: monitor Bitcoin dominance, analyze altcoin trading volumes, track market sentiment through social media, use the Fear and Greed Index.

 

Pay attention to timeframes: the index is calculated based on 90-day dynamics, which can be lagging for short-term trading. For more operational decisions, additional analysis tools should be used.

 

Diversify your portfolio: even during an altseason, not all altcoins perform well. It is important to choose projects with strong fundamentals.

 

Prospects for altseason in 2025

 

Many analysts agree that an altseason could begin in the near future. Here are the main factors supporting this view:

 

Macroeconomic conditions: the expectation of lower interest rates in the US could release significant retail capital that could flow into the crypto market.

 

Institutional interest: growing demand for Ethereum from corporations creates a foundation for altcoin growth. Already 16 companies own 2.6 million ETH worth $12 billion.

 

Regulatory changes: the adoption of the GENIUS Act and CLARITY Act in the US creates a more favorable regulatory environment for cryptocurrencies.

 

Growth in the M2 money aggregate: historically correlates with the growth of the cryptocurrency market, which could support a future altseason.

 

Renowned analyst Peter Brandt recently announced the start of the “altcoin season,” supporting this with a chart of the total cryptocurrency market capitalization excluding Bitcoin, which shows a bullish “Cup with Handle” pattern.

 

Conclusion: should you rely on the Altseason Index?

 

The Altseason Index is a useful tool for identifying market cycles and timing investments in altcoins. However, like any indicator, it is not perfect and should not be the sole argument for making investment decisions.

 

As of now (September 11, 2025), the index shows an upward trend but has not yet reached the value traditionally associated with a full-fledged altseason. This means the market may be in the early stages of capital rotation from Bitcoin into altcoins.

 

Key recommendations:

– Use the index as one of many analysis tools

– Pay attention to the fundamental indicators of individual projects

– Diversify your portfolio even during an altseason

– Set clear profit targets and stop-losses

– Monitor macroeconomic factors and regulatory news

 

Remember that cryptocurrencies are a volatile asset, and investing in them involves risks. Never invest more than you can afford to lose.

ⓒ Yan Krivonosov