The Truth About Altcoin Seasons: History & Cycles

In 2017, Bitcoin’s dominance fell from 86% to 38% over six months. Ethereum rose from $8 to $1,400, while XRP climbed from $0.006 to $3.84. In 2021, Solana rallied from $1.60 to $250. Across every major cycle, altcoin seasons have followed the same pattern of capital rotation.

Every serious participant in crypto markets has heard the term “altcoin seasons.” Most have experienced it firsthand. An altcoin season is the period when Bitcoin consolidates while much of the rest of the market continues to rally. Smaller tokens begin producing returns that far exceed Bitcoin’s, and the conversation shifts from “Will Bitcoin go higher?” to “Which altcoin should I own?”

Most discussions stop at the definition. The conditions that create and end an altcoin season go beyond most explanations. The 2024-2026 cycle also changed several historical patterns. Those changes influence how future altcoin seasons are likely to unfold.

This article provides a complete historical analysis of altcoin seasons. It explains what an altcoin season is, what triggered each major cycle, how on-chain data changed throughout each phase, why every cycle eventually ended, and why the traditional altcoin season playbook proved less effective during the 2024-2026 cycle. It also complements our research on Bitcoin halving cycles and bull market psychology. Altcoin seasons are one phase of the broader crypto market cycle.

Altcoins season — abstract futuristic technology background of altcoin digital cryptocurrency and stochastic market graph volume indicator

Understanding Altcoin Season Cycles

The most widely used definition comes from the Blockchain Center’s Altcoin Season Index. The index measures the percentage of the top 50 cryptocurrencies that have outperformed Bitcoin over the previous 90 days. When at least 75% of those assets outperform Bitcoin, the index classifies the market as being in an altcoin season. When fewer than 25% outperform Bitcoin, it classifies the market as Bitcoin season.

Historical data shows that the index has exceeded 75 only during the strongest altcoin rallies. Those periods occurred in December 2017, January and February 2021, and November 2021. That gives us only three confirmed altcoin seasons in the index’s recorded history. Although the sample size is small, it is large enough to identify characteristics that have appeared consistently across every cycle.

New capital entering the crypto market flows into Bitcoin first. Bitcoin is the most recognized asset, the most liquid, and the easiest to access through regulated investment products. For most retail investors, it is the entry point into crypto. For institutions, it is the default allocation.

As Bitcoin appreciates, its percentage returns gradually slow compared with the earlier stages of the cycle. Investors who have accumulated profits begin looking further along the risk curve for higher returns. Capital rotates from Bitcoin into Ethereum, then into large-cap altcoins, followed by mid-cap projects, smaller-cap tokens, and finally the market’s highest-risk assets.

This sequence has remained one of the most consistent features of crypto market history. Capital moves from the market’s most liquid and least risky assets toward lower-liquidity and higher-risk assets as investors search for returns that larger assets can no longer deliver.

Bitcoin Dominance: The Single Most Important Metric for Tracking Altcoin Season

Bitcoin dominance, the ratio of Bitcoin’s market capitalization to the total cryptocurrency market capitalization, is the clearest macro indicator of where capital sits within the market cycle. Historically, the 60% level has marked the point where capital begins rotating into altcoins. In 2017, Bitcoin dominance fell from 85% to below 60% before declining to roughly 38% at the peak of altcoin season. In 2021, another move below 60% coincided with a broad rally that lifted hundreds of altcoins.

The 60% level is not an exact trigger. It is a historical range where the conditions for sustained altcoin outperformance have often emerged. When Bitcoin dominance remains above 60%, Bitcoin attracts most of the new capital entering the market. As dominance falls below 60% and continues to decline, more capital flows into the broader crypto ecosystem.

One important qualification is that Bitcoin dominance must be interpreted in context. A 60% dominance reading with Bitcoin trading at $90,000 reflects a very different market from a 60% reading with Bitcoin at $30,000. The level itself is less important than its direction and the market environment in which it is changing.

The Historical Altcoin Seasons: A Complete Record

2017

The ICO Boom and the First True Altcoin Season

BTC dominance: 86% → 38% · Duration: ~310 days · Ethereum: $8 → $1,400

The 2017 altcoin season was the first large-scale capital rotation in crypto markets. Between January and December, Bitcoin dominance fell from 86.3% to 38.69% over roughly 310 days. During the same period, Ethereum climbed from $8.19 to $48.62 in the first quarter alone, a gain of nearly 500%. By the end of the year, ETH had reached approximately $1,400, representing a return of more than 17,000% from its January price.

The Primary Driver

The primary driver was the ICO boom. As documented in our Ethereum history research, the ERC-20 token standard made it possible for developers to launch new tokens within hours. The ICO model then allowed those projects to raise capital directly from retail investors without relying on traditional funding channels. A new fundraising model, a strong bull market, and rapidly spreading online narratives combined to fuel the largest wave of capital rotation the crypto market had experienced.

Capital Rotation

Capital followed a clear sequence. Bitcoin led the cycle first. Ethereum followed because it served as the infrastructure for ICO issuance. Capital then flowed into newly launched ICO tokens as exchange listings attracted growing retail participation. Ethereum rose from $8 to $1,400, while projects such as NEO, VeChain, and Cardano generated returns of 50x to 100x. The rally was broad-based. Rather than being concentrated in one sector, it lifted almost every part of the market.

The cycle ended for the same reason Bitcoin’s bull market ended. The market eventually ran out of new buyers. By January 2018, Bitcoin dominance had fallen to roughly 33%, leaving non-Bitcoin assets with almost two-thirds of the total cryptocurrency market capitalization. Much of that value sat in ICO projects with no revenue, no meaningful user base, and no finished product. Prices had moved well beyond underlying fundamentals. Once selling began, the decline accelerated. Assets that had risen 100x without fundamental support fell just as quickly because there was little to support their valuations.

The 2018 bear market erased most of the gains from the 2017 altcoin season. Many ICO tokens lost between 90% and 99% of their peak value, while others became effectively worthless. As discussed in our research on why crypto projects fail, many ICO-era projects raised hundreds of millions of dollars based on whitepapers but never delivered a viable product. The bear market corrected those valuations on a market-wide scale.

2020–2021

DeFi Summer, NFTs, and the Two-Phase Altcoin Season

BTC dominance: 73% → 38% · Two distinct phases · Solana: $1.60 → $250

The 2021 altcoin season differed from 2017 in two key ways. First, capital rotated through specific sectors instead of lifting nearly every altcoin at once. Second, the cycle unfolded in two distinct phases, separated by a sharp Bitcoin correction.

Phase One: DeFi Summer

The first phase lasted from January to May 2021. Between February and May, large-cap altcoins gained an average of 174%, while Bitcoin returned just 2%. The rally centered on decentralized finance (DeFi). Protocols that had built real user bases and generated revenue during the 2020 bear market attracted institutional capital and a new wave of retail investors seeking on-chain yield. Ethereum was the biggest beneficiary, climbing from roughly $730 in January to $4,300 in May. Uniswap, Aave, and Compound, all of which generate protocol revenue, significantly outperformed more speculative tokens.

Bitcoin then corrected from roughly $64,000 in April to $29,000 by June, a decline of about 55% in six weeks. The Altcoin Season Index fell alongside it, wiping out much of the gains from the first phase. The correction also reset market positioning, allowing a second wave of capital rotation later in the year.

Phase Two: NFTs and Layer 1s

The second phase ran from August to November 2021 and was driven by a different narrative. Instead of DeFi, investors focused on NFTs and competition among Layer 1 blockchains. Solana was one of the biggest winners, rising from about $1.60 at the start of the year to more than $250 by November. Avalanche and Polygon also posted exceptional gains as investors sought faster, cheaper alternatives to Ethereum.

The NFT boom pushed Ethereum gas fees to levels that made many DeFi transactions too expensive for ordinary users. That created real demand for competing networks with lower fees and higher throughput. Solana, Avalanche, Fantom, and Terra all benefited as capital rotated toward alternative blockchain ecosystems.

The Cycle Peak

The Altcoin Season Index reached its strongest readings during the major rallies in early 2021 and again in November. The November peak aligned closely with Bitcoin’s all-time high near $69,000. As discussed in our research on bull market psychology, periods when memecoins and small-cap altcoins dominate market performance have historically appeared near the end of crypto bull markets.

724%

Average altcoin gains during the 2021 season

20,000%

Solana’s gain from January to November 2021

The 2021 altcoin season ended as financial conditions tightened and crypto’s internal weaknesses became impossible to ignore. Markets began pricing in Federal Reserve interest rate hikes, reducing liquidity across risk assets. The collapse of Terra/LUNA in May 2022 then triggered a wave of insolvencies that spread throughout the crypto industry, as discussed in our bear market psychology research.

Many of the Layer 1 networks that had benefited from the “Ethereum killer” narrative gave back most of their gains. Avalanche, Fantom, and Terra were among the hardest hit as the narratives supporting them either failed to deliver or collapsed altogether.

2023

The PEPE Interlude, an Altcoin Season Without Bitcoin at All-Time Highs

A selective, narrative-driven rotation that broke from previous cycles

The 2023 altcoin mini-season stands out because it broke one of the market’s longest-running patterns. Earlier altcoin seasons followed Bitcoin reaching or approaching a new all-time high. In 2023, capital rotated into parts of the altcoin market even though Bitcoin remained well below its 2021 peak.

During the spring of 2023 and into 2024, memecoins staged an extraordinary rally without either Bitcoin or Ethereum setting new all-time highs. PEPE was the defining example. Within a month of its launch, the token reached a market capitalization of roughly $1.5 billion, creating life-changing gains for some early buyers and reigniting interest in speculative assets across the market

Unlike 2017 and 2021, this was not a broad-based altcoin season. Capital flowed into a handful of dominant narratives, including memecoins, AI-related tokens, and selected Layer 2 projects, while much of the altcoin market remained in bear market conditions. That concentration marked an important shift in market behavior. The old pattern, where rising liquidity lifted most altcoins, gave way to a more selective environment in which a small number of narratives captured the majority of investor attention and capital. That trend continued throughout the 2024-2026 cycle.

2024–2026

The Broken Template, Why the ETF Era Changed Everything

BTC dominance peaked ~61% · Selective rotation only · Traditional playbook largely failed

The 2024-2026 cycle is the most important case study in the history of altcoin seasons because it broke the pattern established in earlier cycles. The market still experienced capital rotation, but it followed a very different path from 2017 and 2021.

The ETF Effect

The traditional altcoin playbook was straightforward. Bitcoin rallied first, dominance peaked near 60%, and profits gradually flowed into larger altcoins before moving down the risk curve to smaller assets. That pattern worked in 2017 and 2021 because retail investors were the market’s marginal buyers. They entered through Bitcoin, accumulated profits, and then rotated those gains into increasingly smaller altcoins. Millions of individual decisions created the broad altcoin seasons that lifted most of the market.

The introduction of spot Bitcoin ETFs changed that dynamic. As discussed in our Bitcoin ETF research, institutional capital entering through ETFs rarely rotates into smaller altcoins. Pension funds, asset managers, and other institutional investors buying products such as IBIT are not reallocating those positions into micro-cap tokens. Instead, ETF inflows remain concentrated in Bitcoin and, to a lesser extent, Ethereum through its own spot ETFs.

The Rotation That Never Came

The shift became visible in market data. CryptoQuant CEO Ki Young Ju summarized it by saying that the traditional Bitcoin-to-altcoin rotation has “basically disappeared.” CryptoQuant also reported that BTC-denominated altcoin trading volume on centralized exchanges had fallen to its lowest level since 2021.

Bitcoin dominance reached roughly 61.4% in November 2024 before beginning to decline. In previous cycles, that move would have triggered a broad rotation across the altcoin market. Instead, the rotation remained concentrated in Ethereum and a small group of large-cap assets. During the summer of 2025, Bitcoin dominance fell by roughly 16% in six weeks while Bitcoin consolidated near $111,000. Ethereum gained about 72% against Bitcoin over the same period, but the move failed to spread across the broader altcoin market.

A More Selective Market

Capital is now concentrated in far fewer assets than in previous cycles. Only around 50 cryptocurrencies have market capitalizations above $1 billion. At the same time, projects with real revenue, active users, or institutional demand have increasingly outperformed narrative-driven tokens. To the extent that the 2024-2026 cycle produced an altcoin season, it was a selective rotation rather than the market-wide rally seen in 2017 and 2021.

As of July 2026, Bitcoin is trading near $75,000 while Bitcoin dominance remains around 58%. Those figures, combined with a Fear and Greed Index below 20, suggest that the broader market environment has not yet shifted into the conditions that historically supported a broad altcoin season. A declining Bitcoin dominance and improving relative strength in Ethereum point to the early stages of selective large-cap rotation, not the broad participation that defined previous cycles.

The Sector Rotation Sequence in Altcoin Seasons

Within every altcoin season, capital does not flow into every asset at the same time. Instead, it follows a recurring sequence that reflects differences in liquidity, risk, and investor confidence. Although the leading sectors change from one cycle to the next, the order of capital rotation has remained remarkably consistent.

Phase 1: Ethereum Leads

Ethereum almost always moves before the broader altcoin market. The ETH/BTC ratio has historically led major altcoin rallies by roughly two to four weeks. During the 2021 cycle, ETH/BTC climbed from 0.027 to 0.084, a gain of more than 200%. When Ethereum begins outperforming Bitcoin in BTC terms, it has often marked the start of broader strength across the altcoin market.

Ethereum leads because it sits at the intersection of liquidity, institutional access, and utility. Investors reducing Bitcoin exposure but not yet ready to move into smaller, higher-risk assets typically rotate into Ethereum first. As discussed in our Ethereum history research, Ethereum remains the primary settlement layer for DeFi, tokenized assets, and smart contract applications, giving it a stronger fundamental foundation than most other altcoins.

Phase 2: Large-Cap Layer 1s and Major Protocols

Once Ethereum establishes leadership, capital typically rotates into other large-cap Layer 1 networks and established DeFi protocols. Assets such as Solana, Avalanche, BNB Chain, and leading decentralized finance projects have historically attracted the next wave of capital because they offer greater upside than Ethereum while remaining liquid enough for large investors.

The projects leading this phase have changed from cycle to cycle. In 2017, Ethereum itself filled this role as the emerging smart contract platform. In 2021, Solana, Avalanche, and Fantom benefited from the “Ethereum killer” narrative. During the 2024-2026 cycle, Solana maintained its position while Ethereum Layer 2 networks such as Base and Arbitrum attracted increasing developer activity and user adoption. Although the leading projects change, the underlying pattern remains the same: capital follows the platforms that investors believe will capture the next wave of growth.

Phase 3: Mid-Cap Sector Leaders

Once the largest altcoins begin to lose momentum, capital typically rotates into mid-cap projects tied to the cycle’s strongest narratives. During 2021, that meant DeFi governance tokens in the first phase and NFT-related projects in the second. In a cycle driven by artificial intelligence, the next wave would likely include AI infrastructure and AI-focused tokens.

This phase has historically produced some of the largest percentage gains of any stage in altcoin seasons. Returns of 5x to 20x have not been uncommon, but the risks increase as liquidity falls. With fewer buyers and sellers, even modest inflows or outflows can move prices sharply.

Phase 4: Small-Cap Speculation and Memecoins

The final stage of altcoin seasons reaches the market’s highest-risk assets: small-cap tokens with limited liquidity, little fundamental support, and prices driven primarily by narrative momentum and retail FOMO. As discussed in our memecoin research, this stage has historically delivered both the largest short-term gains and the steepest losses. It is also one of the clearest late-cycle signals.

When memecoins dominate social media discussions and trading volumes, capital has typically reached the final stage of the rotation. By that point, most investors willing to move further down the risk curve have already done so. With few new buyers left to sustain prices, the market becomes increasingly vulnerable to a reversal.

75%

Percentage of the top 50 cryptocurrencies that must outperform Bitcoin over 90 days for the Altcoin Season Index to classify the market as an altcoin season.

That threshold has been reached only three times since the index began tracking the market: December 2017, January-February 2021, and November 2021. The rarity of confirmed altcoin seasons is an important reminder that they are not a regular feature of every bull market. Instead, they are concentrated events that emerge only when several market conditions align.

On-Chain Data During Altcoin Seasons

Price charts show the outcome of altcoin seasons. On-chain data shows how capital moves before those price changes become visible. By tracking exchange flows, Bitcoin dominance, stablecoin liquidity, and derivatives positioning, investors can determine whether capital is moving into altcoins or leaving the market.

Exchange Flows and Rotation Timing

Capital rotation appears in exchange data before it shows up in price action. When Bitcoin holders transfer coins to exchanges while stablecoin balances rise, investors are preparing to reallocate capital. If those funds move into altcoins instead of leaving the crypto market, exchange inflows for major altcoins increase soon afterward.

The timing differs from one cycle to another, but the sequence has remained consistent: Bitcoin exchange inflows, rising stablecoin balances, and then increasing inflows into altcoins. Because prices respond to capital flows, exchange data can provide an earlier indication of market rotation than price charts.

Bitcoin Dominance and Stablecoins

Bitcoin dominance becomes less reliable when viewed on its own because the growth of stablecoins changes the calculation. As USDT, USDC, and other stablecoins grew into a market worth more than $200 billion, they increased the total cryptocurrency market capitalization without affecting Bitcoin’s market capitalization. As a result, Bitcoin dominance can fall even when capital is not moving into altcoins.

After accounting for stablecoin growth, Bitcoin dominance in 2026 is closer to 62%, indicating that Bitcoin still holds a dominant share of the market even after pulling back from recent highs. Stablecoin-adjusted dominance provides a clearer measure of capital rotation. Data providers such as Glassnode and Lambda Finance publish adjusted dominance metrics that account for this effect.

Funding Rates and Leverage

Funding rates on perpetual futures become increasingly positive during the later stages of altcoin seasons. That means traders holding long positions pay higher fees to keep those trades open. As discussed in our bull market psychology research, elevated funding rates show that bullish leverage has become crowded, increasing the risk of large liquidation cascades.

Historically, the combination of elevated funding rates and strong memecoin performance has marked the final stage of altcoin seasons. Together, they show that leverage and market optimism have reached levels where even modest selling pressure can trigger a rapid reversal.

Why Altcoin Seasons Always End the Same Way

Every altcoin season has ended in the same way because the flow of capital eventually reaches its limit. The process is not unique to crypto. It follows the same pattern seen in every market driven by speculation.

The Buyer Pool Runs Out

The rotation that powers altcoin seasons depends on a steady stream of new buyers. Capital moves from Bitcoin to Ethereum, then into large-cap altcoins, mid-cap projects, and finally the smallest, highest-risk assets. Each stage depends on new participants buying from those who entered earlier. By the time capital reaches memecoins and micro-cap tokens, there are few buyers left willing to take on more risk at higher prices.

The Rotation Reverses

Once the market reaches that point, almost any catalyst can trigger a reversal. A macroeconomic event, a regulatory announcement, or a wave of liquidations can start the decline. As prices fall, leveraged positions unwind, and capital moves back through the market in reverse, from small-cap tokens to large-cap altcoins, then to Ethereum, Bitcoin, and finally stablecoins. The decline unfolds much faster than the advance because fear spreads more quickly than confidence.

The Pattern Repeats

The sequence has remained consistent across every major altcoin season. Bitcoin leads, large-cap altcoins follow, mid-cap projects accelerate, and small-cap tokens and memecoins produce the biggest gains. The cycle then reverses. The decline is not a break in the pattern. It is the final stage of the cycle, resetting valuations before the next accumulation phase begins.

Bitcoin leads. Large-cap altcoins follow. Mid-cap projects accelerate. Small-cap tokens surge. Then the cycle reverses. Every major altcoin season has followed that sequence.

What Has Changed and What Hasn’t In Altcoins Season

The 2024-2026 cycle raised an important question: has the pattern behind altcoin seasons changed, or has the market’s structure changed while the underlying capital rotation remains the same?

What Has Changed

The biggest change is the composition of Bitcoin buyers. Spot Bitcoin ETFs now hold more than $118 billion in assets under management across products such as IBIT, FBTC, and ARKB. That capital behaves differently from the retail capital that dominated earlier cycles. Investors buying Bitcoin through ETFs are far less likely to rotate profits into smaller altcoins, reducing the broad capital flows that fueled the market-wide rallies of 2017 and 2021.

What Hasn’t Changed

The underlying pattern of capital rotation remains intact. Ethereum’s performance relative to Bitcoin continues to provide one of the earliest indications that capital is moving beyond Bitcoin. Capital still flows through familiar stages, beginning with Ethereum before reaching other large-cap networks and, later, higher-risk assets. The difference is that the rotation now reaches fewer projects and favors stronger fundamentals over broad speculation.

Future altcoin seasons are likely to remain more selective than those of 2017 and 2021. Projects with sustainable revenue, active users, or institutional demand are better positioned to attract capital, while many narrative-driven tokens may never experience the broad rallies seen in earlier cycles. As discussed in our research on why crypto projects fail, only a small share of crypto projects have achieved lasting product-market fit. Recent market cycles have made that divide much more visible.

What I’m Watching

The metrics I track most closely for altcoin season are the ETH/BTC ratio, stablecoin-adjusted Bitcoin dominance, and the Altcoin Season Index, in that order from leading to lagging.

ETH/BTC Comes First

The ETH/BTC ratio comes first. It has led altcoin season by 2-4 weeks across previous cycles. A sustained uptrend in ETH/BTC, not a single session’s move but a multi-week trend above the 50-day moving average, has historically marked the point where capital begins rotating beyond Bitcoin. However, it also produced the most false positives during the 2024-2026 cycle. I therefore confirm it against the broader dominance trend before concluding.

Bitcoin Dominance

Stablecoin-adjusted Bitcoin dominance below 60% and falling has historically preceded the strongest periods of altcoin outperformance. As of mid-2026, stablecoin-adjusted dominance sits at 62%, down from its November 2024 peak. Conditions are moving toward that threshold but have not reached it.

The Altcoin Season Index confirms the move instead of predicting it. By the time it rises above 75, the strongest gains have already occurred in most cases. It is more useful for showing when you’ve missed the move than for identifying the entry point.

For mid-2026, the historical context is clear. The 50-60% dominance range has consistently produced the best risk-adjusted altcoin returns, especially among the top 125 altcoins excluding Bitcoin and Ethereum. The market now sits in that range. The question is if institutional ETF ownership prevents the broad rotation seen in previous cycles or if the historical pattern returns as retail participation recovers.

The pattern has repeated three times with enough consistency to deserve attention. It broke once for reasons tied to institutional adoption. If it breaks again or returns depends on who the next marginal buyer is and how they behave compared with the retail participants who drove earlier cycles.

That is the only question worth answering right now. Everything else in altcoin season analysis follows from it.

Key Takeaways

Altcoin season begins when at least 75% of the top 50 crypto assets outperform Bitcoin over 90 days. The market has reached this threshold only three confirmed times: December 2017, January-February 2021, and November 2021. It is a concentrated, infrequent phase, not a recurring part of every bull market.
The trigger has remained consistent across every historical instance. New capital enters through Bitcoin, Bitcoin’s percentage gains slow as its market cap expands, retail investors rotate profits into progressively riskier assets, and Bitcoin dominance falls from above 60% toward its historical floor around 33-38%.
The rotation follows the same sequence each cycle. Ethereum leads by 2-4 weeks, followed by major Layer 1 blockchains, then mid-cap sector leaders, and finally small-cap tokens and memecoins. When memecoins dominate attention and trading volume, the market has historically entered the final stage of altcoin season before reversing.
The 2024-2026 cycle broke the traditional pattern because spot Bitcoin ETF inflows, with $118 billion in AUM, shifted Bitcoin ownership toward institutions that do not rotate into altcoins. As a result, the broad retail-driven rotation that defined the 2017 and 2021 cycles weakened.
The ETH/BTC ratio still leads altcoin season by 2-4 weeks and remains the strongest early indicator. Stablecoin-adjusted Bitcoin dominance below 60% and falling has historically preceded the strongest periods of altcoin outperformance. Meanwhile, the Altcoin Season Index serves as confirmation. By the time it exceeds 75, most of the rotation has already taken place.
Future altcoin seasons will likely become more selective than previous cycles. Sectors and assets with sustained revenue or institutional demand should outperform, while the long tail of low-quality assets may not benefit from the broad market lift that defined 2017 and 2021. As the market matures, price performance makes the gap between stronger businesses and purely narrative-driven assets easier to see.