A major crypto trader suffered an $8.2 million loss after a leveraged position in the ARC perpetuals market collapsed on the decentralized derivatives platform Lighter. The incident forced the exchange to deploy its backstop liquidity and activate auto-deleveraging mechanisms to contain systemic risk.
In a series of posts on X, Lighter explained that the whale accumulated an outsized long position over several days, driving total open interest in ARC to roughly $50 million. Around 600 traders and market makers took the opposite side of the trade.
The position began to unravel when ARC’s price fell at approximately 6:00 pm ET on Wednesday. Roughly $2 million of the exposure was liquidated directly through the order book, while the remaining balance was transferred into Lighter’s liquidity provider pool (LLP) and categorized under a high-risk strategy framework.
To stabilize the market, the platform triggered auto-deleveraging (ADL), partially closing profitable short positions to facilitate an orderly unwind. At its peak, the LLP temporarily absorbed nearly 200 million ARC — valued at about $14.7 million — before the exposure was gradually reduced as prices continued to decline.
Risk caps limit LP losses to $75,000
Despite the scale of the liquidation, losses for liquidity providers were contained. According to Lighter, only about $75,000 in LP funds were impacted, as the ARC market operates within a segregated risk bucket rather than drawing from the platform’s entire liquidity pool. Traders holding short positions against the whale ultimately booked profits.
“In the end, the big long trader lost around 8.2 million USDC, the LLP absorbed about $75,000 in losses, and the short traders who took the risk of betting against the position ended up profitable,” Lighter wrote.
Following the episode, Lighter introduced additional safeguards. In a notice posted on its website, the platform said it implemented a $40 million open interest cap for ARC and shifted the pair to a capped liquidity strategy backed by roughly $100,000 in USDC capital. If that liquidity is depleted, the system will now automatically switch to auto-deleveraging (ADL) to reduce exposure.
The exchange added that similar open interest and liquidity caps could be rolled out for other assets.
Manipulation concerns on decentralized platforms
The incident adds to broader concerns about potential price manipulation on decentralized trading venues. In August last year, four whales were accused of manipulating the price of Plasma (XPL) on Hyperliquid after the token surged roughly 200% to above $1.80 within minutes.
In June, DeFi protocol Resupply experienced a security breach in its wstUSR market, leading to $9.6 million in losses. The attacker allegedly exploited price manipulation linked to its integration with the synthetic stablecoin cvcrvUSD.
