xyz:SKHYNIX Flash Crash on Hyperliquid: Incident Report
At the open of the Korean pre-market session on July 28th, the SK Hynix perpetual market on Hyperliquid (xyz:SKHYNIX, a HIP-3 builder-deployed market operated by Trade XYZ) flash-crashed 18% in a matter of seconds. The crash was triggered by a single-share SK Hynix order error on Nextrade (NXT), South Korea's alternative trading venue, which executed at the daily lower price limit ₩1,272,000 and roughly 30% below the previous close. Trade XYZ's oracle ingested this print as the market reference price, repriced the perp from $1,131.40 to $954.99 and triggered a liquidation cascade.
Nearly 1,000 accounts were liquidated, representing $57.4M in position value and $17.3M in realized losses. The backstop mechanism then auto-deleveraged (ADL) profitable short positions, force-realizing $10.8M in profits across dozens of accounts. The underlying stock recovered to ₩1.7M within a few minutes.
No funds were stolen and no smart contracts were exploited. This was an oracle-design failure: the relay of a real but wholly unrepresentative one-share print, with no safeguards to reject it.
How Trade XYZ's Oracle for the xyz:SKHYNIX Market Was Configured
Per Trade XYZ's public documentation for its Korean equity markets:
Price sources. The oracle sources KRW-denominated executable quotes from institutional data providers, alongside real-time USD/KRW FX rates. The perp's USD price is computed by dividing the KRW price by the USD/KRW rate (e.g., ₩886,000 ÷ 1,444.10 = $613.53).
Session handling. The oracle tracks three live sessions (KST): pre-market 08:00–08:50, main session 09:00–15:30, and after-hours 15:40–20:00. Outside these windows, including overnight and weekends, the market runs on Trade XYZ's internal pricing.
Fallback logic. Internal pricing also activates if there is a gap of more than 30 seconds between external oracle datapoints.
What was missing. The configuration did not contain outlier rejection, volume or trade-size weighting, cross-venue sanity check, or a bounds test against the prior close. At the 08:00 pre-market open, NXT is effectively the only live external venue (KRX's main session does not open until 09:00), so a single print in a nearly empty book became the oracle's reference price with no corroboration required.
Under HIP-3, the market deployer, Trade XYZ, controls the oracle, mark price, and external price feeds. Hyperliquid core supplies infrastructure only. Trade XYZ's 500,000 HYPE deployer stake is slashable by validators, but slashed stake is burned rather than distributed, so slashing provides no restitution path for affected traders.
The Loss Timeline
08:00:00 KST (23:00:00 UTC July 27). NXT's pre-market session opened. An apparent order error executed exactly one share of SK Hynix at ₩1,272,000, the daily lower limit, ~30% below the previous close (sources place the prior close between ₩1,785,000 and ₩1,816,000, implying a 28.7–30% deviation on the print). With almost no resting bids at the open, this single odd-lot trade became the session's traded reference price.
~08:00:04 KST. The bad print propagated through Trade XYZ's oracle. The SKHYNIX oracle price dropped from $1,131.40 to $954.99 (−15.6%). The market's price bands capped the applied move; the raw print implied approximately −29%.
~08:00:07 KST. Liquidations began (~2.7 seconds after the oracle update). The cascade of forced selling pushed perp executions as low as ~$900, a peak-to-trough move of −17.9%.
Liquidation wave. 960 long accounts were liquidated: $57.4M in positions closed, ~$17.3M in margin losses realized.
ADL wave. With the liquidation engine unable to fully offload positions into the crashed book, the backstop auto-deleveraged profitable shorts, force-closing ~100 accounts and realizing ~$10.8M in profits.
Recovery. SK Hynix on NXT traded back to ~₩1.7M within approximately two minutes. The oracle recovered with the venue; the liquidations and ADL closures were final.
What Nexus Mutual's Hyperliquid Core Listing Covered
The Hyperliquid Core Protocol Cover Annex designates five protocols: the Hyperliquid Bridge, Hyperliquid Perpetuals Core, Hyperliquid Spot Order Book, Hyperliquid HLP Vault, and "Hyperliquid HIP-3 Trade[XYZ] Perpetual Markets." The xyz:SKHYNIX market falls squarely within the coverage. Although HIP-3 markets are builder-deployed and their oracles are deployer-controlled, this Annex was written to include the Trade XYZ markets by name, and Hyperliquid is a designated network in the Annex.
Under the Protocol Cover wording, Covered Events are:
2.1. a smart contract code bug or error resulting in the Designated Protocol being used in an unintended way; or
2.2. A sudden and widespread economic event that is clearly outside the normal or intended operation of the Designated Protocol and affects multiple users where the Loss is caused by: 2.2.1. Oracle Failure; or 2.2.2. Oracle Manipulation; or 2.2.3. Liquidation Failure; or 2.2.4. Governance Takeovers.
Oracle Failure is defined as incorrect price feed data being used where, for non-stablecoin assets, the error exceeds 2.5%, arising from: a faulty oracle configuration; or a lack of proper safeguards preventing an unauthorized party from providing pricing updates; or an incorrectly updated fixed-rate oracle.
Would Nexus Mutual Have Covered this Loss Event
Yes, this loss event qualifies as a Covered Event for the wrongfully liquidated long positions. The event was sudden (roughly seven seconds from session open to liquidation cascade), widespread, and affected multiple users (960 liquidated longs plus ~100 ADL'd shorts). It was clearly outside the normal or intended operation of the Designated Protocol.
Liquidated longs: covered. They were wrongfully liquidated as a result of the Oracle Failure. Absent the bad print, they would still hold their positions and margin.
ADL'd shorts: not covered. Their unrealized gains were themselves an artifact of the incorrect price. Had the oracle reported correctly, there would have been no crash, no paper profits, and nothing to realize. The mutual does not indemnify the loss of profits that the covered peril itself conjured.
How Members Can Calculate Claimable Amounts
For a covered member with a wrongfully liquidated long position, the wording's loss mechanics work as follows:
Start with the realized margin loss. The deposited margin lost through the wrongful liquidation, valued at the time the loss occurred (using coingecko.com exchange rates where conversion is needed). The basis is realized loss of deposited funds, not position notional: the relevant aggregate is the ~$17.3M realized, not the $57.4M in liquidated position value. Unrealized or counterfactual profits are not claimable.
Subtract any Reimbursements (clause 5.2). Trade XYZ has announced it will reimburse eligible liquidation losses. Any amount a member receives from that distribution reduces the claimable Loss dollar-for-dollar. A member made whole by Trade XYZ has no residual claimable Loss.
Apply the Deductible and cover cap (clause 6). Claim Amount = min [Loss − (Deductible × Cover Amount), remaining Cover Amount]. The deductible percentage is as specified for this listing (5% under the standard wording unless the Annex specifies otherwise).
Next Steps: Waiting for Trade XYZ's Compensation Plan
Trade XYZ has announced that it will cover eligible liquidation losses from the incident as a "one-time discretionary decision," with eligibility criteria to be published and distributions expected in the coming days.
Members should note that claims remain subject to the cover wording's evidentiary requirements and to Claims Assessor voting. For any questions regarding filing your claim, please contact the Nexus Mutual team.
