sUSD depeg, explained: Why Synthetix's stablecoin fell below $0.70

In a significant and concerning event in the cryptocurrency space, sUSD, the native stablecoin of the Synthetix protocol, saw its value plummet to $0.68 on April 18, 2025.

In a significant development, sUSD, the native stablecoin of the Synthetix protocol, dropped to $0.68 on April 18. This represents a 31% drop from its intended peg of 1:1 with the US dollar, a threshold that is fundamental to the concept of stablecoins.

Stablecoins are designed to maintain a stable price, which is especially important for their role as a reliable store of value within decentralized finance (DeFi) applications.

This stability is maintained through various technical and economic mechanisms within the blockchain protocol itself and the actions of users. In essence, the protocol's design and the collective behavior of users combine to keep the stablecoin's value close to its target.

However, this stability can be affected by several factors, such as:

* Changes in the protocol that alter the incentives for users to act as liquidity providers or traders.

* A collective shift in user behavior, such as a mass sell-off or withdrawal of liquidity.

* External events that impact the broader cryptocurrency market, such as the price of Bitcoin or Ethereum.

The drop in sUSD's value is a topic of discussion and concern among members of the cryptocurrency community.

Why did sUSD fall below its peg?

sUSD depeg was triggered by a protocol shift (SIP-420) that lowered collateralization and disrupted peg-stabilizing incentives. Combined with Synthetix’s (SNX) price drops and liquidity outflows, confidence in sUSD weakened.

Understanding SIP-420 and its impact

The protocol-owned debt pool introduced by SIP-420 allows SNX stakers to delegate their debt positions to a shared pool with a lower issuance ratio, shifting the focus from individual collateralization to collective capital efficiency. This move is intended to boost capital utilization, simplify the staking experience, and provide richer yield opportunities to stakers.

On the other hand, solo staking is discouraged by raising its collateralization ratio to 1,000%, aiming to encourage participation in the shared debt pool.

Before SIP-420, users who minted sUSD had to over-collateralize with SNX tokens, maintaining a 750% collateral ratio. This high requirement ensured stability but limited capital efficiency.

To improve this, SIP-420 aimed to reduce the collateral ratio to 200% and introduce a shared debt pool, distributing the risk across the protocol rather than individual users.

While this change made it easier to mint sUSD, it also removed the personal incentive for users to buy back sUSD when its price dropped below $1.

If a user had a $100,000 SNX position and minted $75,000 sUSD, they would be personally motivated to purchase sUSD at $0.9 to repay their debt early and minimize interest accrual.

However, with the shared debt model, this self-correcting mechanism weakened. If a user saw sUSD trading at $0.7, they might not feel compelled to buy it back, especially if they weren't personally engaged in lending or borrowing sUSD.

This lack of personal incentive was crucial in the events leading up to sUSD's depeg.

What happened to sUSD?

The combination of increased sUSD supply and reduced individual incentives led to a surplus of sUSD in the market. At times, sUSD comprised over 75% of major liquidity pools, indicating that many users were offloading it at a loss.

This oversupply, coupled with declining SNX prices, further destabilized sUSD's value.

At one point, SNX dropped to lows of $1.5, having started the year above $3. This price decline weakened the perceived backing of sUSD, as SNX was used to collateralize the stablecoin.

Moreover, the market reacted negatively to the prospect of a "dump" of sUSD to repay the shared debt pool, which would decrease the value of the stablecoin further.

Ultimately, sUSD fell below the $0.7 level, a move that was largely attributed to a lack of liquidity on offers above $0.7, according to data from Bitswap.

This lack of liquidity, combined with the factors mentioned earlier, facilitated the rapid fall of sUSD's price.

The implications of sUSD losing its peg

The events unfolding with sUSD highlight the complexities of maintaining stablecoins, especially in the volatile cryptocurrency market.

While sUSD is recovering slowly, the incident had several implications:

* Loss of confidence in Synthetix and its ecosystem.

* Potential outflows from liquidity providers and lenders seeing negative returns.

* A broader narrative of stability being challenged in the cryptocurrency realm.

This isn't the first time Synthetix has experienced volatility. The protocol, known for its decentralized synthetic asset platform, has seen fluctuations during past market cycles. For instance, Synthetix