BTC-ETH Funding Flipped Overnight: BTC Now −2.92%/yr, ETH +2.99%/yr

The Overnight Flip: From +6.24%/yr to −2.92%/yr

The previous insight in this series — published at 08:30 UTC on August 3 — documented BTC perp funding at +6.24%/yr and ETH at −0.20%/yr. In dollar terms: BTC longs were paying approximately $378K/day in aggregate across the platform’s $2.21B BTC open interest. ETH longs at $1.74B OI were collecting a negligible amount (near-zero negative rate).

At 08:28 UTC on August 4 — 24 hours later — both readings have reversed:

Source: Hyperliquid metaAndAssetCtxs API. Aug 3 data from the 5-day spread snapshot. pp = percentage points. Informational only.

BTC’s funding swung 9.16 percentage points lower in 24 hours. ETH moved 3.19 percentage points higher. The two largest perp markets on Hyperliquid have swapped which side carries a premium over spot.

The Dollar Flow: $546K/Day Swing in BTC Alone

Funding flows are determined by open interest size multiplied by the annualised rate. Over 24 hours, the BTC long position shifted from paying to collecting:

Daily flow = OI × (|funding APR| ÷ 365). Negative = longs pay shorts; positive = shorts pay longs. Aggregate across all Hyperliquid positions. Informational only.

The net swing in BTC’s daily funding flow for longs is $378K + $168K = $546K/day — from paying $378K to collecting $168K. This arithmetic reflects the change in the premium relationship between BTC’s perp price and its spot oracle, not any directional prediction.

For ETH, the daily flow moved from a small collection (+$9.5K/day) to a payment of $148K/day. ETH’s OI was also slightly larger on August 4 ($1.81B vs $1.74B), meaning slightly more exposure is now on the paying side.

Price Context: Both Assets Up ~2% While Funding Diverged

Over the 24-hour window from August 3 (08:30 UTC) to August 4 (08:28 UTC), both assets rose in price:

Price data from Hyperliquid mark price and prevDayPx. 24h change = (markPx − prevDayPx) ÷ prevDayPx. Snapshot: 4 Aug 2026, 08:28 UTC. Informational only.

Both assets moved positively in price. The divergence is in the perp premium: ETH’s perp is now pricing above its spot oracle (positive funding), while BTC’s perp has moved below its spot oracle (negative funding). The cost structure of holding a long position in each asset has inverted from the previous day’s reading.

The Mechanics: How the Hourly Cap Creates Reversals

Hyperliquid calculates funding each hour as a function of the premium between the perp mark price and the spot oracle. The cap is 0.00125% per hour (10.95%/yr). When BTC was at +6.24%/yr on August 3, it was running at roughly 57% of the cap rate. BTC has previously traded at the 10.95%/yr cap itself (documented on August 3) and at negative rates within the same 24-hour window.

The swing from +6.24% to −2.92%/yr in 24 hours is a 9.16-point move in the annualised rate, or equivalently a shift of roughly 0.001045% per hour in the raw funding rate. At $2.1B OI, each 0.0001%/hr shift in the raw rate changes the hourly cost to all longs by approximately $2,100. The daily change in aggregate BTC long cost from this overnight reversal is the equivalent of $546K/day.

This does not describe why the change occurred in terms of price causation — only that the premium relationship between BTC’s perp and its oracle moved from above-spot to below-spot over this interval. The same observation applies to ETH moving in the opposite direction: ETH’s perp moved from below its oracle to above it.