1M butterfly premiums diverge across crypto majors

The reading

What the evidence says

The clearest cross-asset distinction is in 1M BF25, the average wing implied-volatility premium over at-the-money volatility. Across the matched daily crypto endpoints, BTC 1M BF25 changed by +0.18 vol points ^[1] to 1.13 vol points ^[2], while ETH changed by +0.07 vol points ^[3] to 1.89 vol points ^[4]. SOL moved in the opposite direction, changing by -0.21 vol points ^[5] to 1.62 vol points ^[6]. This is a divergence in wing premiums relative to ATM, rather than evidence about absolute wing volatility or directional demand. Nearby butterfly changes reinforce the distinction: BTC 1W changed by +0.16 vol points ^[7] to 1.18 vol points ^[8], ETH 1W by +0.04 vol points ^[9] to 2.00 vol points ^[10], and SOL 1W by -0.18 vol points ^[11] to 1.42 vol points ^[12]. At 2W, BTC BF25 changed by +0.04 vol points ^[13] to 1.13 vol points ^[14], ETH by +0.12 vol points ^[15] to 2.04 vol points ^[16], and SOL by -0.19 vol points ^[17] to 1.48 vol points ^[18]. BTC’s 1M BF25 absolute daily move ranked at 94.2nd percentile ^[19] against its eligible full captured history, 52 observations (observed sampling; 08 Sep 2026–06 Nov 2026) ^[19]; that individual magnitude rank does not establish rarity of the cross-asset configuration.

ATM volatility, meaning at-the-money implied volatility, shows why the butterfly distinction should not become a claim of broad volatility expansion in BTC and ETH. BTC 1M ATM IV changed by -0.15 vol points ^[20] to 37.82% ^[21], ETH 1M by +0.05 vol points ^[22] to 52.43% ^[23], and SOL 1M by -1.11 vol points ^[24] to 54.39% ^[25]. The corresponding 1W ATM changes were -0.07 vol points ^[26] for BTC, +0.05 vol points ^[27] for ETH and -1.06 vol points ^[28] for SOL. SOL’s 2W ATM change of -1.93 vol points ^[29] also rules out describing its easing as confined to 1W. Its ordered current ATM levels—1W 56.18% ^[30], 2W 54.77% ^[31] and 1M 54.39% ^[25]—retain a downward-sloping front curve despite the declines.

Directional asymmetry is more aligned at 1M than the butterfly premiums suggest. RR25 measures call-versus-put implied-volatility asymmetry; negative readings indicate higher put volatility. BTC 1M RR25 changed by -0.45 vol points ^[32] to -3.54 vol points ^[33], ETH 1M by -0.45 vol points ^[34] to -4.06 vol points ^[35], and SOL 1M by -0.95 vol points ^[36] to -1.35 vol points ^[37]. Each deepened an existing downside bias. At 1W, BTC RR25 changed by -0.24 vol points ^[38] to -3.43 vol points ^[39], and ETH by -0.38 vol points ^[40] to -6.04 vol points ^[41]. Thus BTC and ETH combine widening relative butterfly premiums with more negative skew across 1W and 1M, while SOL combines narrowing butterfly premiums with a tenor-dependent skew adjustment.

Spot and realized volatility qualify the options divergence. Over the matching daily crypto interval, BTC spot changed by -0.06% ^[42], ETH by +0.20% ^[43], and SOL by -0.61% ^[44]. Over the common trailing weekly window, realized volatility recomputed from canonical minute prices was 38.51% ^[45] for BTC, 49.75% ^[46] for ETH and 58.66% ^[47] for SOL. Forward 1W IV minus that trailing realized volatility stood at +0.17 vol points ^[48] for BTC, +2.60 vol points ^[49] for ETH and -2.48 vol points ^[50] for SOL. SOL’s negative spread accompanies its lower 1W ATM IV and narrowing 1W butterfly premium, while BTC and ETH retain positive spreads despite widening 1W butterfly premiums. BTC’s separate volatility benchmarks also differ: DS30 was 43.11 vol points ^[51], BVIV was 41.85 vol points ^[52], and BVIV minus DS30 was -1.26 vol points ^[53]. These are distinct benchmark constructions, not substitutes for BTC 1W ATM IV. During the crypto comparison interval, Cointelegraph reported restrictions on transfers involving MEXC. That chronology makes payment access relevant background, but does not identify a cause for SOL’s opposing 1M butterfly move or the shared 1M skew adjustment.