The answer is: not necessarily. A long-term stable APY often means losses haven't been recorded in the books yet. Once they are confirmed, the value of your shares can shrink in an instant.
DeFi vaults often advertise APY as "yield," but in economic terms, vaults are risk products. When bad debt appears in the underlying markets, different vault contract versions handle it completely differently — V1.0 immediately books the loss and reflects it in the share price, while V1.1 hides the loss until you try to withdraw.
Morpho's liquidation rules define bad debt in three tiers: LTV < LLTV means healthy; LLTV < LTV ≤ 1/LIF means it can be liquidated; once 1/LIF < LTV, liquidators cannot cover the full debt even after taking all collateral, and the remaining gap is bad debt. This gap shows up as a reduction in total supply in the lending market. As a vault depositor, you bear a share of that gap.
Version V1.0: APY drops clean and fast
In a V1.0 vault, the share price drops the moment bad debt is recognized. The on-chain mechanism: each adapter reports the actual value of underlying assets through realAssets(), which automatically decreases when bad debt happens. When the vault accrues interest, if it detects that realAssets is lower than the recorded totalAssets, it adjusts total assets downward. The share price is calculated by convertToAssets() — when totalAssets falls, so does the share price. The loss is automatically shared among all depositors in proportion to their holdings, with no exceptions.
Version V1.1: APY stays smooth as if nothing happened
V1.1 is designed completely differently. It removes the automatic bad-debt recognition from V1.0. When bad debt occurs in the underlying market, the share price does not drop. The bad debt is delayed and passed on to the last withdrawer — if you withdraw after bad debt appears and no external capital injection covers that loss, you are the one who takes the hit.
This is the most direct version-dependent explanation for "stable APY but slowly declining net share value": V1.0 reflects losses instantly, while V1.1 delays the reflection, making it look like the net value is intact while the actual underlying assets have already shrunk.
Risk warning
Morpho Vaults V1.1 docs explicitly state an important note: if a V1.1 vault is configured to a V1.0 vault through an adapter, losses from the V1.0 vault will not be reflected in the V1.1 share price. This means your APY can appear steady even while the underlying assets are suffering losses. In November 2025, a roughly $93 million shortfall at Stream Finance triggered chain-linked bad debt, with approximately $25.4 million in potential bad debt exposed on Morpho and multiple markets hitting 100% utilization. If you held shares in a V1.1 vault at that time, your APY might still have been positive the moment bad debt was confirmed, but you could no longer withdraw the full amount.
Step 1: Check if your vault is V1.0 or V1.1
The version determines when and how losses reflect on your shares. You can check the vault's contract version on Morpho's official interface or a block explorer. V1.0 immediately lowers the share price when bad debt occurs; V1.1 does not automatically recognize the loss, and bad debt is delayed to the last withdrawer. Confirming the version number helps you judge whether a stable APY may be hiding bad debt.
Step 2: Check if the underlying market has had a bad debt event
Verify whether bad debt has already occurred but isn't yet shown in your shares. You can search on Etherscan or Dune for the Liquidate event logs of the market that the vault's adapter connects to, and look for the badDebtAssets field. If that field is greater than 0, it means the market has already generated bad debt. This lets you confirm whether there is "occurred but not yet recognized" bad debt in the underlying market.
Common failure reasons
Many people keep depositing just because the APY stays stable. But V1.1 vaults' stable APY may be precisely because the bad debt is being "socialized late." By the time withdrawals are hindered or the curator announces the bad debt, you may have already missed the exit window. In the Altura vault incident, 21% of TVL was requested for withdrawal within 24 hours, directly triggering a liquidity crisis.
Next steps
If you find your vault is V1.1 and the underlying market has experienced a bad debt event but the share price has not yet been adjusted, consider promptly evaluating whether to withdraw early. If you are a vault manager, you can consider a "capital injection" to cover the bad debt gap — calculate the loss ratio of the vault in that market, supply an equivalent amount of assets to that market to restore the share price. For depositors, the most direct verification is a small "test withdrawal" — withdraw a tiny amount and check whether the actual received amount equals the number of shares × the current share price. If the numbers don't match, it means bad debt is already on the path of delayed socialization.
