The pattern of Bitcoin's four-year bull-bear cycles—why has it never been broken?

In October 2025, Bitcoin once again hit a new all-time high of $126k.
At this moment, just about 18 months after the April 2024 fourth halving.
This is no coincidence—after the 2017 top, 18 months later, the halving;
the 2021 top also occurred 18 months after the halving.
When we look back at Bitcoin's history, a shocking fact stands before us:
from the first halving in 2012 to today, thirteen years have passed,
and this "four-year cycle" pattern has never been broken.

01. A thirteen-year-long "coincidence"
Bitcoin was born in 2009, and the first bull market that truly caught the market’s attention appeared in 2013.
At that time, in November 2012, Bitcoin completed its first halving,
reducing the block reward from 50 to 25 coins.
A year later, the price skyrocketed from teens of dollars to $1,200.
Most people thought it was just a fleeting speculative bubble.
Then, in July 2016, the second halving occurred.
In the following 2017, Bitcoin soared from over $400 to nearly $20k,
with the entire cycle increasing by 80 to 90 times.
The market began to notice the word "halving," but most still saw it as coincidence.
In May 2020, the third halving took place, and in 2021, Bitcoin reached $69k.
Three halvings, three bull markets.
Within 12 to 18 months after each halving, the top was reached, followed by a 70% to 85% crash,
then about a year of bear market bottoming, and everything started over.
This rhythm is as precise as a mechanical clock.

Entering 2025, after the fourth halving in April 2024,
Bitcoin hit a new high of $126k on October 6, 2025.
18 months—completely consistent with the previous two cycles.
Those predicting "this time is different" have once again been proven wrong.
Thirteen years of data do not lie:
although the gains after halving have gradually decreased—
the first nearly 9000%, the second about 2800%, the third about 700%—
the existence of a bull market itself has never been absent.
This is not superstition like "carving a boat to seek a sword,"
but a structural pattern repeatedly validated by market behavior.
Patterns can be questioned, but facts cannot be erased.

02. Why four years? Mysticism?
Many ask: if the four-year cycle is just a coincidence, why does it perfectly coincide with the halving?
The answer lies in Bitcoin’s underlying code.
Satoshi Nakamoto designed Bitcoin with a strict rule:
every time 210k blocks are mined—about four years—
the mining reward is halved.
This is not a temporary marketing gimmick, but a deliberately embedded monetary issuance mechanism,
aimed at countering the endless over-issuance of traditional fiat currencies.
How does this mechanism drive prices?
The core logic is two words: supply and demand.
If demand remains unchanged, the daily new supply of Bitcoin drops sharply from 900 to 450 coins,
directly reducing the selling pressure the market needs to absorb.
And Bitcoin’s total supply is forever capped at 21 million coins,
most of which are already locked by long-term holders.
The only coins truly circulating in the market are the new ones mined daily.
When this new supply is suddenly halved, and demand does not decrease proportionally,
the upward pressure on price becomes irreversible.
This is the simplest economic principle, yet it is often overly complicated by many.

Of course, relying solely on the supply shock from halving cannot explain the entire rise of each bull market.
The ICO frenzy in 2017, institutional entry and DeFi Summer in 2021,
all acted as demand amplifiers in their respective cycles.
But it’s worth noting that each halving occurs at the bottom of a bear market—
in 2015, Bitcoin fell from $1200 to $164, then halving arrived;
in 2018, from $20k to $3,000, halving arrived;
in 2022, from $69k to $15k, halving arrived again.
Is this just coincidence?
I prefer to believe it’s an intrinsic self-healing mechanism of Bitcoin, this “digital life form.”
It reignites scarcity at the bleakest moments of the bear market,
planting the seeds for the next bull run.

03. Human nature never changes
Supply and demand are fundamental, but they are not everything.
If the four-year cycle of Bitcoin were just a simple economic model,
it would have been eliminated by arbitrageurs long ago.
What truly sustains this thirteen-year pattern is a more fundamental factor—human nature.
In every bull market, we hear almost the same stories:
- “This time is different, institutions are in, forever bull market.”
- “Bitcoin is now mainstream, no more 80% crashes.”
- “Halving is fully priced in, no excess returns.”
These voices appeared in 2013, 2017, 2021, and 2025.
And each time, the market teaches everyone a brutal lesson:
markets can change, but human nature does not.
This cycle in 2025 is especially ironic.
In early 2024, Bitcoin spot ETFs were approved in the US,
with giants like BlackRock and Fidelity flooding in,
institutional holdings reaching record highs.
Suddenly, the market was filled with optimistic narratives of “eternal bull.”—
institutions are smart money, they won’t chase and sell like retail traders,
Bitcoin’s volatility will decrease, and cycles will disappear.
But after reaching $126k in October 2025,
Bitcoin plummeted about 25% in less than a month,
once again falling below $90k.
Market sentiment shifted from euphoria to panic,
eerily similar to the top structures of 2017 and 2021.
Those who believed “this time is different” were once again taught a lesson.

04. Why does this happen?
Because regardless of whether market participants are retail or institutional,
the core driver of trading has never been “rationality,” but greed and fear.
Institutions are not gods; they also face redemption pressures and risk controls.
When driven by greed to leverage and build positions,
their behavior is no different in essence from retail traders.
Conversely, the most desperate moments of each bear market
are precisely when halving is about to arrive.
In 2015, Bitcoin fell from $1200 to $164, the market said “Bitcoin is dead,”
then in 2016, halving occurred, and the bull market of 2017 followed.
In 2019-2020, Bitcoin hovered around $3000-$4000, the market said “no more bull,”
then in 2020, halving happened, and the 2021 bull market ensued.
In 2022, the bear market bottomed at $15k, and the market again declared Bitcoin dead,
then in 2024, halving arrived, and in 2025, a new all-time high was made.
When you think “this is really the end,”
the cycle is actually brewing the next starting point.

05. The cycle still exists, just in a different form
As we enter 2026, discussions about whether the “four-year cycle” has failed heat up again.
Some point out that this cycle’s Bitcoin gains are only 7 to 8 times,
far below the nearly 20 times in 2017;
altcoins are sluggish, Bitcoin’s market dominance remains near 59%;
market sentiment is cold, lacking the previous nationwide frenzy.
Many analysts believe that with institutional funds dominating the market,
the four-year cycle is being broken.
These observations are not without reason.
The bull market of 2024-2025 is indeed different:
the rise is more gradual, volatility is more contained, and frenzy is absent.
But I tend to believe that the cycle has not been broken,
it has been “suppressed” and “prolonged.”
Continuous buying from ETFs provides a “liquidity cushion,”
weakening the depth of crashes.
Miners are no longer forced to sell in large quantities like before;
they now hedge risks with derivatives, and in 2025, even rare phenomena like miner address balances increasing appeared.
The 2022 bear market’s decline of only 77%—less than 86% in 2014 and 84% in 2018—
shows that crashes are becoming shallower, and surges are slowing.
But the outline of the cycle remains clear.
The cycle has not been eliminated; it has only changed form.
Just like adolescence, when people grow taller and voice deepens,
the human lifecycle does not disappear.
Bitcoin’s “maturity” makes its volatility more refined,
but it does not change its origin in code, its dependence on supply and demand, or its fundamental human nature.

06. Patterns are never meant for prediction
Writing this, I recall an interesting phenomenon:
In the crypto world, those who truly make money are never the clever people who frequently predict “how high this time will go,”
but the “fools” who quietly dollar-cost average during the bleakest bear markets,
and quietly exit during the craziest bull runs.
They are not making predictions; they are following the flow.
Bitcoin’s four-year cycle pattern is never meant for precise top-and-bottom predictions,
but as a reminder to “do the right thing at the right time.”
It tells us: when you think Bitcoin is finished,
it might be the best time;
when you think Bitcoin can go to the moon,
it’s probably time to be cautious.
In 2028, the fifth halving will arrive.
By then, the block reward will drop to 1.5625 coins,
and daily new supply will further decrease to about 225 coins.
Looking back from today, this pattern may be questioned, mocked, or even declared “broken.”
But if you ask me, will it be broken?
My answer is: Bitcoin’s code is still running, human nature has not evolved.
The four-year cycle will most likely continue as scheduled.
By then, people will start a new round of “this time is different” debates.
And the cycle will quietly keep turning—like a clock that never speaks, yet has never been wrong.