Just five days after announcing its integration with Binance Wallet, ConcreteXYZ was caught in an on-chain transaction that raised eyebrows across the DeFi community.
On March 17, Twitter user Bamboo Tom (@0xAzathoth_) shared an Etherscan screenshot showing Concrete Vault's rebalance: 1,000,000 USDT exchanged for 995,082.36 USDC, resulting in a loss of about $4,997 and a slippage of 0.49%. Both USDT and USDC are dollar-pegged stablecoins. On major DEXs like Curve, such swaps typically incur less than 0.01% slippage. 0.49% is roughly 50 times the norm.
“A $5,000 loss on a million? How is that even possible? Treating users' money like toilet paper?” Bamboo Tom posted bluntly.
The incident struck a nerve because Concrete had just launched a promotion with Binance Wallet. Some users noticed their deposit balances and withdrawal amounts both dropped by “0.1%,” effectively losing money the longer they stayed — a phenomenon likely tied to slippage in vault rebalancing.
Rebalance Trade Exposes Pricing Flaw
Developed by Blueprint Finance, Concrete is marketed as an “institutional-grade yield vault infrastructure on Ethereum.” Users deposit USDT, USDC, WBTC, USDe, and other assets into the vault; the platform deploys them via delta-neutral arbitrage strategies to earn yield, targeting ~8.5% APY, with a 7-day redemption period. The protocol currently holds $900 million in TVL and has processed over $11.2 billion historically. Backed by YZi Labs (ex-Binance Labs), Polychain Capital, VanEck, Tribe Capital, and Hashed, it raised $17 million in total funding.
On March 12, Concrete announced its integration with Binance Wallet, enabling wallet users to deposit USDT directly into the vault for yield, alongside a promotional campaign offering up to $200,000 in rewards (minimum stake: 100 USDT). Just five days later, deposit and withdrawal discrepancies surfaced.
Lack of Slippage Protection or Router Misconfiguration?
The community suspects the issue lies in the vault's rebalance routing logic. Large stablecoin swaps typically go through deep liquidity pools like Curve's 3pool with tight slippage tolerance. The 0.49% loss suggests the route selected a thin liquidity source, or no slippage protection was set, allowing the contract to execute at a highly unfavorable rate. Every rebalance eats into user principal.
Concrete's ctStableUSDT contract (0x6503de9fe77d256d9d823f2d335ce83ece9e153f) is an upgradeable proxy audited by Cantina, Halborn, and Zellic. But audits focus on security vulnerabilities, not operational fairness — automatic slippage settings for users fall outside their scope.
No Official Response
As of press time, Concrete has not issued any statement on X or its official channels regarding the incident.