MetronomeDAO said roughly 6,367 msETH and 4.57 million msUSD now circulating in the market have no collateral behind them, a backing gap worth about $15.7 million at current prices. In a post-mortem published on July 30, the protocol said trading bots spent months exploiting delayed price data in its swap feature.
The hole amounts to about 31% of all msETH in existence and 16% of all msUSD. Metronome said that if those tokens fall in price and the shortfall is realized, the losses would hit liquidity providers, the users who deposited msETH and msUSD into pools on exchanges including Curve and Aerodrome to earn fees.
The team added that the damage is confined to the swap module. Its Morpho lending markets, MetBasis product, and core minting protocol are still operating normally.
CoinGecko data showed msETH down 25% over the past 24 hours to $1,378, while trading volume rose roughly ninefold to $51.7 million. msUSD was changing hands at $0.737, or 25% below $1.
According to DefiLlama, Metronome Synth holds $10 million in total value locked across Ethereum, Base, and Optimism, down from $17.56 million on Thursday.
How the stale price gap was exploited
Metronome Synth, launched in 2023, lets users deposit collateral such as ETH, USDC, and WBTC, then mint synthetic assets against it. Those synths include msETH, which tracks the price of ETH, and msUSD, which tracks the dollar.
The protocol’s central design is that every synth in circulation should match a debt position. Someone in the system should owe that token back to the protocol and should have posted collateral worth more than the liability. That one-to-one relationship between synth supply and debt is what Metronome means by backing.
Metronome also runs a swap module that allows traders to exchange msETH for msUSD and back with zero slippage. To calculate how much msUSD one msETH is worth, the module reads the ETH/USD price from Chainlink, one of the largest oracle providers feeding real-world data onto blockchains.
According to the post-mortem, the problem is that Chainlink’s feed does not update continuously. A new on-chain price is posted only when the market moves beyond a preset threshold or after a timed interval. On Base, that deviation threshold is 0.15%. On Ethereum, it is 0.5%. Between updates, the on-chain price can lag the live market by minutes.
Trading bots watched both prices at the same time and swapped whenever the gap favored them, buying whichever synth the stale oracle was undervaluing. Each trade gave the bot more value than it returned to the protocol. The difference accumulated over time as what Metronome called “unbacked float,” or synths circulating without any debt position behind them.
Why the fee model failed
Metronome said it had already treated stale pricing as a known risk and set swap fees to absorb it. The fee was 0.45% per swap on Base, three times the oracle feed’s deviation threshold there, and 0.55% on Ethereum. The operating assumption was simple: no bot should be able to profit from a price gap smaller than the fee.
That assumption did not hold. The team said the oracle feed spent much longer outside its expected accuracy band than the design had anticipated.
Metronome said it repriced all 241,292 swaps in the protocol’s history, covering $3.6 billion in volume across Ethereum, Optimism, and Base, using the exact oracle reading available at the moment each transaction was executed.
Its full oracle report showed that since launch on Base, the ETH/USD feed has been outside its 0.15% band for 18.5% of all minutes. The team also said response times deteriorated sharply in 2026, with March through July marking the worst five-month stretch in the protocol’s history. The post-mortem said the root cause was “the latency of the Chainlink price at swap execution, a variable which Metronome’s fee design did not properly account for, and one that particularly deteriorated on Base.”
Metronome said it has shared the dataset with Chainlink and is “in active discussion with them.” Chainlink had not publicly responded at the time of writing.
The team said it first noticed backing slipping in the first quarter of 2026 and spent months working through possible explanations. Diagnosis was delayed in April and May after the $292 million Kelp DAO bridge exploit pushed Metronome to shut off synth operations because of concerns around LayerZero, the cross-chain messaging network its synths use to move between blockchains. By June, once systems were back online and the gap was still widening, the oracle issue was the only explanation left.
Recovery plan funded by the treasury
Metronome said the protocol is still operating, but damaged, and that its recovery plan relies on treasury resources rather than forced user haircuts.
Swapping has been pushed close to a halt. Fees on all synth pairs have been raised high enough to keep volume minimal until an architecture upgrade is complete. The protocol can also now charge different fees in each direction to defend against one-sided order flow.
To guard against a run, the treasury has borrowed and looped $34 million notional in synthetic asset positions that profit if the synths trade below their reference price. It has also committed about $6.5 million in what it described as “last-to-leave” liquidity, or protocol-owned pool deposits that will stay in place until backing is restored so ordinary liquidity providers are not competing with the treasury to exit first.
Metronome said that if msETH or msUSD fall by roughly 30%, those defensive positions would generate enough profit to buy back and burn every unbacked token and fully restore backing.
The team wrote, “That is the point at which current treasury positions are sufficient to fully settle the gap, not a guarantee that price cannot move further.”
How the gap closes without a crash
If prices do not fall that far, the protocol expects a slower repair process. Metronome said more than $51 million in outstanding debt continues to generate interest, and that revenue will be used for gradual buybacks and burns until every synth is backed again.
The team said talks with partners could bring in additional capital for the effort.
Liquidity providers are not facing forced losses, according to Metronome. They can either sell their synths into the market now or remain in the pools, continue earning yield, and wait for the peg to strengthen. MET holders are unaffected, the team said, and token buybacks plus esMET distributions will continue as planned. Backing data is being published on a Dune dashboard.
The post-mortem added that before the defensive positions were put in place, “synthetic LPs were roughly 30% unbacked globally, and Metronome had been paying to incentivize unbacked, unproductive synthetic assets in circulation.”
Earlier pool losses
This is not the first time Metronome has absorbed losses at the pool level. In July 2023, its msETH-ETH Curve pool was drained during the Vyper compiler exploit that hit multiple Curve pools.