Bitcoin has recorded 10 three-sigma trading days in 2026, more than the eight seen during all of 2018, according to CoinDesk’s analysis. The comparison is striking because bitcoin’s annualized volatility has fallen to about 46% this year from roughly 84% in 2018, leaving investors with a market that looks calmer on the surface but still produces abrupt tail events.
Three-sigma days have outpaced the 2018 bear market
CoinDesk counted 10 trading sessions this year in which bitcoin’s daily price move deviated by at least three standard deviations from its recent trading pattern. In 2018, the full-year total was eight, a year in which bitcoin’s market value fell 73%.
Traders use sigma to describe how far a price move strays from normal behavior. To measure those sessions, CoinDesk compared each daily move with bitcoin’s 30-day realized volatility, a gauge of how much the asset has typically moved each day over the previous month. Any day in which the move reached at least three times that level, in either direction, was classified as a three-sigma day.
In a normal bell-curve distribution, about 95% of moves fall within two sigma and 99.7% within three sigma. That makes a three-sigma move rare by definition. A high count suggests that even if overall volatility is cooling, the asset remains prone to sudden jolts.
Lower volatility has not removed extreme repricing
The data point to a market that has become quieter over time without losing its capacity for sharp dislocations. Relative to recent volatility, bitcoin is seeing more unusually large moves this year than it did in 2018, even though the absolute size of those moves has become smaller.
Bitcoin’s annualized volatility is about 46% this year, versus 84% in 2018. The average size of its three-sigma moves is about 7%, down from around 10% eight years ago.
"Bitcoin still goes through long periods of calm and then suddenly reprices. That hasn’t changed. The market has matured, institutions, ETFs and liquidity are all much deeper, so ordinary trading days are calmer. But the shocks haven’t gone away: macro, leverage, positioning," said Nicolas Quatravaux, head of EMEA at institutional crypto liquidity network Paradigm.
The contrast also stands out against other volatile assets. Since 2024, bitcoin’s volatility has been roughly in line with Nvidia at about 47%. Over the same period, however, bitcoin logged 26 three-sigma days, compared with eight for Nvidia, 16 for the S&P 500 and 12 for gold.
Why falling volatility can mislead VaR-based models
Persistent extreme moves create a problem for investors who use volatility-based risk models to determine bitcoin exposure.
One widely used metric is value-at-risk, or VaR, which estimates how much a portfolio could lose on a bad trading day. Some VaR models lean heavily on recent price behavior. If trading stays quiet for an extended period, the asset can appear less risky in the model.
That means declines in bitcoin’s 30-day, 90-day and 180-day volatility measures may encourage investors to increase exposure. Depending on how the model is built, though, that apparent drop in risk may fail to capture the possibility of unusually large losses.
VaR can also produce a loss threshold without showing how severe losses may become once that threshold is breached. That is the tail-risk problem: rare but very large losses that sit outside an asset’s normal trading pattern. Bitcoin’s repeated three-sigma moves suggest investors still need to account for those outcomes even as day-to-day volatility falls.
"Standard VaR metrics do not properly assess the full tail risk, which is one of the main reasons the industry has moved toward Expected Shortfall and similar measures that take tail risk into account," said Deribit CEO Luuk Strijers.
Expected Shortfall focuses on how severe losses are on the worst trading days, not just how often those days occur. Used alongside or instead of VaR, it gives investors a better sense of the damage extreme losses can inflict.
"If portfolio targets do not account for tail risk, then a calmer bitcoin does indeed encourage larger allocations in a portfolio, which makes a sudden price jump more disruptive to that portfolio," Strijers said. He added that these three-sigma risks can be hedged with bitcoin options.
Macro shocks and leveraged options positions remain key drivers
Market participants said unpredictable macro events and heavily leveraged options positioning are the two main forces behind these high-VaR trading days.
Quatravaux said this year offers a clear example.
"The year started slowly, flows rotated into tech stocks, and a series of DeFi hacks pushed people toward selling volatility and structured products for yield. Then you get Trump, the Iran war, the Federal Reserve, and everyone is short volatility in a range. One headline is enough to give you an outlier day," he said.
When traders bet that prices will remain relatively stable, risk can build inside those positions. In practice, that often means selling, or shorting, options, effectively selling insurance against large price swings in exchange for premium income.
That works when markets stay quiet. But when a macro headline hits and prices move sharply, sellers can find themselves on the wrong side and rush to cover, turning a move into a larger shock.
Alexander S. Blume, co-founder and CEO of U.S. Securities and Exchange Commission-registered investment adviser Two Prime, pointed to one especially popular version of the trade: call overwriting. Investors sell call options against bitcoin they already hold, giving up part of the upside in exchange for steady premium income.
"I think that despite the compression in overall volatility, the large increase in derivatives positioning still allows large moves to happen relatively frequently. Right now, call overwriting is a highly crowded trade. When we get upside like we have seen over the past month, it creates a short squeeze and amplifies volatility," Blume said.
The market appears more resilient than before
There is also evidence that the market is handling these shocks better than it did in earlier years.
On Sept. 21, the date of bitcoin’s most recent three-sigma jump, Paradigm facilitated a record $6.7 billion in options volume.
"This time we didn’t see, or hear of, any trading desk taking major losses," Quatravaux said.
"Participants are much more mature than they were a few years ago, risk management has improved a lot, and there is more institutional capital in the market, so a difficult month is often just a difficult month," he said.
Still, he said investors should not expect these violent moves to disappear.
"They are here to stay. Ten years of data show these days have not vanished as the market has matured, because macro shocks are not going anywhere," Quatravaux said.
