hybrid-perps-spec

Funding Rate Settlement Scenarios

Funding rate settles every 8 hours (UTC 00:00 / 08:00 / 16:00).

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SC-FS-001: INTERNAL Position Funding — Long Pays Short

Preconditions:

• User holds BTC INTERNAL long: size=0.1 BTC, mark_price=$100,000
• Current funding rate = +0.01% (positive = longs pay shorts)

Calculation:

Funding Payment = 0.1 × 100,000 × 0.0001 = $1.00

Expected Results:

• User account deducted $1.00 (long pays)
• Platform counterparty account credited $1.00
• balance_logs entry written: type = “funding_fee”
• funding_settlements table entry written
• Liquidation price recalculated (funding erodes margin; liq price moves adversely)

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SC-FS-002: HYPERLIQUID Position Funding — Short Receives Funding

Preconditions:

• User holds ETH HYPERLIQUID short: size=5 ETH, mark_price=$4,000
• Current funding rate = +0.005% (positive = longs pay, shorts receive)

Calculation:

Funding Receipt = 5 × 4,000 × 0.00005 = $1.00 (short receives)

Expected Results:

• HL settles +$1.00 on platform HL account (automatic)
• Platform mirrors same amount to user account: user available_balance +$1.00
• Platform mirror amount = HL actual settlement amount (must match exactly)
• If Platform mirror ≠ HL actual → trigger reconciliation alert

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SC-FS-003: Negative Funding Rate — Short Pays Long

Preconditions:

• BTC funding rate = -0.005% (negative = shorts pay longs)
• User holds BTC INTERNAL long: size=0.1, mark_price=$100,000

Calculation:

Long receives = 0.1 × 100,000 × 0.00005 = $0.50

Expected Results:

• User (long) available_balance +$0.50
• Platform counterparty (short) pays out $0.50
• Liquidation price moves slightly down (funding adds margin buffer for longs)

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SC-FS-004: Mid-Period Open — Funding Settlement Behavior

Preconditions:

• Funding period: UTC 00:00 ~ 08:00
• User opens BTC INTERNAL long at UTC 04:00 (mid-period)

Expected Results:

• Position participates in UTC 08:00 funding settlement at the full period rate
• No pro-rata calculation based on time held in period (mirrors HL behavior)
• First settlement participation: UTC 08:00

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SC-FS-005: Funding Reconciliation — Platform vs HL Drift Detection

Preconditions:

• Multiple users hold HYPERLIQUID positions
• UTC 00:00 funding settlement

Steps:

1. HL completes funding settlement; platform HL account changes by +$500
2. Platform mirrors funding for each user’s HYPERLIQUID position using HL’s published rate
3. Platform mirrored total = $498
4. Drift detected = $2 (0.4%)

Expected Results:

• Drift 0.4% < 1% → write deviation_log, no alert triggered
• Drift > 1% → Slack alert
• Drift > 5% → P0 emergency; halt HL routing for this asset
• Daily drift summary → reconciliation_logs