Overview
Belt Finance launched in early 2021 during the BSC DeFi explosion, offering two products: yield-optimized vaults that auto-compounded deposits across BSC lending protocols (Venus, Alpaca Finance, Fortube), and a StableSwap AMM similar to Curve for low-slippage stablecoin trading. The "belt" tokens (beltBUSD, beltUSDT, etc.) represented yield-bearing versions of underlying stablecoins, deposited across multiple lending protocols for optimized returns.
At peak, Belt Finance held over $1 billion in TVL, making it one of the largest BSC DeFi protocols. The protocol was a product of its time — BSC offered high-yield farming opportunities, and Belt made them accessible through a simple deposit-and-forget interface.
On May 29, 2021, an attacker exploited Belt Finance for approximately $6.2 million using a flash loan attack. The attacker manipulated the pricing within Belt's strategy vaults by depositing and withdrawing large amounts in a specific sequence that exploited the way Belt calculated the value of its belt tokens across the underlying lending protocols. The attack revealed fundamental vulnerabilities in Belt's multi-protocol value accounting.
Smart Contracts
Belt Finance's contracts implemented a multi-strategy vault system where deposits were distributed across multiple lending protocols. The critical vulnerability was in the pricing mechanism for belt tokens — the contracts calculated the value of deposited assets across multiple protocols in a way that could be manipulated through large deposits and withdrawals within a single transaction. The StableSwap AMM used Curve's invariant for stablecoin swaps. The code quality was typical of the BSC DeFi era — functional but not rigorous. The complex multi-protocol deposit/withdrawal accounting created attack surfaces that a more careful implementation would have avoided.
Security
Security was catastrophic. The $6.2M exploit exposed fundamental flaws in the protocol's value accounting. The attack was a variant of the "share price manipulation" vector common in vault-style protocols, but Belt's multi-protocol strategy amplified the impact. Pre-exploit audits (by Haechi) failed to identify the vulnerability. After the exploit, additional vulnerabilities were found in the remaining contracts, leading to further concerns. The exploit was not sophisticated by DeFi standards — it was a well-known attack pattern applied to Belt's specific accounting logic. This suggests the protocol was rushed to market without adequate security review.
Yield Generation
Pre-exploit, Belt's yield generation was competitive for BSC — auto-compounding across Venus, Alpaca, and other protocols produced double-digit APYs boosted by farming rewards. Post-exploit, yield generation effectively ceased. The protocol's reputation made it impossible to attract new deposits, and underlying BSC farming yields declined across the board. Any remaining vaults offer negligible returns. The protocol is not active in any meaningful sense.
Adoption
Belt Finance had massive adoption during BSC's peak — billions in TVL and thousands of active depositors. The exploit triggered a confidence crisis, and TVL collapsed. The broader BSC DeFi decline further accelerated Belt's abandonment. Current adoption is effectively zero. The protocol is not integrated into modern BSC DeFi. The belt.fi website may still be accessible but the protocol is abandoned.
Tokenomics
BELT token was distributed through farming incentives with a capped supply. Post-exploit, the token lost nearly all value. No meaningful governance activity exists. Protocol revenue is zero. The token trades at a tiny fraction of its all-time high, with negligible liquidity and volume. BELT is a dead asset with no path to recovery. Any remaining circulating tokens represent pure speculation on a defunct protocol.
Risk Factors
- Protocol Exploited: $6.2M flash loan exploit permanently destroyed protocol viability and trust.
- Abandoned Development: No meaningful team activity, updates, or maintenance since decline.
- Additional Vulnerabilities: Post-exploit analysis revealed further smart contract issues beyond the initial exploit.
- Dead Ecosystem: BSC yield farming ecosystem has broadly contracted, eliminating Belt's underlying yield sources.
- Token Worthless: BELT has no utility, governance function, or revenue backing.
- No Recovery Path: Reputation damage, absent team, and market evolution make any revival impossible.
Conclusion
Belt Finance exemplifies the worst of BSC's 2021 DeFi boom — a protocol that accumulated over $1 billion in TVL without adequate security review, then lost $6.2M in a well-known attack pattern that should have been caught in auditing. The exploit was not exotic; it was a flash loan-based share price manipulation that more rigorous development practices would have prevented. Belt's failure damaged not just its own depositors but contributed to the broader erosion of confidence in BSC DeFi. The protocol is dead, BELT is worthless, and the primary takeaway is that TVL is not a proxy for security. A billion dollars in deposits doesn't protect against a developer who didn't properly validate their vault's share price calculations.