Week of 15 December 2025: Bitcoin edges up 0.55% while Ether falls 2.01% on light volume
When Bitcoin and Ether move in opposite directions over a week but track each other hour by hour, what does the difference tell us about relative strength?
BTC rose from 88,172.16 to 88,658.86 (+0.55%) while ETH fell from 3,063.49 to 3,002.02 (-2.01%). Hourly correlation was 0.92, and the two still ended the week in opposite directions. Both traded at about 0.6 times their prior 12-week dollar volume, and funding stayed near zero.
What the data shows. BTC opened the week at 88,172.16 and closed at 88,658.86, a gain of 0.55% that ranks at the 50th percentile of the 409 weeks on record. Its high of 90,365.85 came at 15:00 UTC on Wednesday 17 December, in the same hour as the week's largest hourly move, -2.72%. The low of 84,450.01 followed at 20:00 UTC on Thursday 18 December, giving a 7.01% range from high to low. ETH opened at 3,063.49, reached its high of 3,177.50 at 10:00 UTC on Monday 15 December, and set its low of 2,775.19 at 19:00 UTC on Thursday 18 December, a 14.5% range, before closing at 3,002.02 (-2.01%, 35th percentile). Both assets put their best day on Friday 19 December (BTC +3.06%, ETH +5.34%). BTC closed in the upper third of its weekly range (71.1%), ETH in the middle third (56.4%).
What it does not show. The two assets moved together hour by hour (correlation 0.92) yet ended the week in opposite directions. The data cannot say who traded, why ETH fell further, or whether the gap will persist. Both dollar volumes came in below the prior 12-week average (BTC 0.63 times, ETH 0.60 times), so the week's readings rest on lighter-than-usual activity.
What a careful desk would check. Realised volatility was 51.0% annualised for BTC and 68.5% for ETH, against ranges of 7.01% and 14.5%. BTC sat 29.64% below its 52-week high and ETH 39.17% below, so the relative weakness is measurable against different baselines. The ETH/BTC ratio fell 2.54% over the week; one possible reading is that Ether simply swung more widely inside a shared hourly pattern, but the correlation alone cannot establish this, so a desk would check whether the ratio move continues before treating it as a change in relative value.
Funding. Funding, the periodic payment between long and short holders of perpetual futures, averaged 0.0056% per eight hours for BTC (range -0.0009% to 0.01%) and 0.0024% for ETH (range -0.0032% to 0.0092%). Rates this close to zero describe a near balance between the two sides and carry little cost in either direction.
What would change this reading
- If a later week closes below this week's low of 84,450.01 for BTC or 2,775.19 for ETH, Friday's recovery reads as a bounce inside a broader decline.
- If the ETH/BTC ratio keeps falling after this week's -2.54%, the divergence becomes a trend in relative strength rather than a single-week gap.
- If volume returns towards its prior 12-week average while funding stays near zero, the light activity of this week reads as a quiet spell rather than a shift in positioning.
Terms
- realised volatility
- how much the price actually swung over a period, expressed as a yearly percentage
- funding rate
- the periodic payment between long and short holders of a perpetual futures contract; positive means longs pay shorts
- ETH/BTC ratio
- the price of one Ether expressed in Bitcoin, which rises when Ether outperforms Bitcoin