Bitcoin's volatility has plunged, but extreme price swings are more frequent than in 2018
Bitcoin recorded 10 days in 2026 when its price moved at least three standard deviations from its recent trading pattern, according to a CoinDesk analysis — more than the eight such days logged across the whole of 2018, when the cryptocurrency lost 73% of its value. The finding matters because bitcoin's overall volatility has fallen sharply, a combination that can lead risk models to understate the chance of sudden, outsized losses.
Traders measure outsized moves in 'sigma', a gauge of how far an asset's price typically deviates from its normal behaviour. CoinDesk compared each day's price move with bitcoin's 30-day realised volatility — how much the price typically moved each day over the previous month — and counted any day that moved at least three times that amount, up or down, as a '3-sigma' day. In a normal bell-shaped distribution, about 95% of moves fall within 2-sigma and 99.7% within three, which is why traders use the threshold to flag unusual swings. The result is a market that has calmed without losing its capacity for shocks: bitcoin's annualised volatility is about 46% this year against 84% in 2018, while its 3-sigma moves have averaged roughly 7%, down from about 10% eight years ago. Since 2024 bitcoin has been about as volatile as Nvidia, at roughly 47%, yet has logged 26 three-sigma days over that period, compared with eight for Nvidia, 16 for the S&P 500 and 12 for gold. "Bitcoin still goes through long quiet stretches followed by sharp repricings, and that hasn't changed. The market has matured, with more institutions, ETFs and much deeper liquidity, so the average day is calmer. But the shocks haven't gone away: macro, leverage, positioning," said Nicolas Quatravaux, head of EMEA at Paradigm, an institutional liquidity network in crypto derivatives.
The persistence of extreme moves poses a problem for investors sizing positions with volatility-based risk models. Value-at-risk, or VaR, estimates how much a portfolio could lose on a bad day, and some versions lean heavily on recent price fluctuations, so a long stretch of calmer trading can make an asset appear less risky and encourage larger allocations. VaR also estimates a loss threshold without saying how severe losses could become beyond it — the tail risk that bitcoin's recurring 3-sigma days illustrate. "Standard VaR measures do not properly assess the full tail risk, and this is one of the main reasons industry has been moving towards Expected Shortfall and similar measures, that do take tail risk into account," said Luuk Strijers, chief executive of crypto options exchange Deribit. He added that the 3-sigma risk can be hedged with bitcoin options.
Market participants attribute the outsized days to a mix of unpredictable macro shocks and heavily leveraged options positioning. The risk builds when traders sell options — in effect, insurance against large price swings — to pocket the premium, a strategy that works while markets stay quiet; when a headline lands and prices lurch, those sellers are caught on the wrong side and their rush to cover can turn a move into a shock. Alexander S. Blume, co-founder and chief executive of Two Prime, an SEC-registered investment adviser, pointed to one popular version of that trade, known as call overwriting, in which investors sell call options on bitcoin they already hold in exchange for steady income. "I believe that, despite tempered volatility on the whole, the heavy increase in derivatives markets positioning allows for large moves to still occur somewhat frequently. At present, call overwriting is a highly crowded trade. When we see a move up, like the past month, it creates a short squeeze that amplifies the moves," Blume said.
Quatravaux said the market is absorbing these jolts better than it once did. On 21 September, the day of bitcoin's latest 3-sigma jump, Paradigm facilitated a record $6.7 billion in options trades. "This time we haven't seen or heard of any desk taking a bad hit," he said, adding that participants are much more sophisticated than a few years ago, risk management has improved a lot, and there is more institutional money in the market, so a tough month stays a tough month. "They'll stick around. Ten years of data shows these days haven't gone away as the market matured, because macro shocks aren't going anywhere," Quatravaux said.
