Pendle created PT tokens, which separate the yield from the principal of a yield-bearing asset. PT holders don’t earn interest over time; instead, they buy the token at a discount and wait until maturity to redeem it for exactly 1:1 in the underlying asset.
The problem is that many lending protocols, including Aave, accept PT as collateral. The logic sounds reasonable: the closer PT gets to maturity, the closer its value gets to 1:1, and the lower the risk of mispricing.
But as maturity approaches, the Pendle AMM for that PT usually stops trading a few days beforehand to avoid unusual slippage. Liquidity gradually dries up, spreads widen, while the maturity contract still runs on schedule whether or not the market is ready.
Currently, about $67.4 million in collateral on Aave is held in PT-AUSD, which matures on 08/10/2026 — in two days. The oracle’s valuation of this PT depends on the implied interest rate curve, not its actual trading price on the AMM.
When AMM liquidity dries up before the maturity date, the oracle price and the actual price can diverge without anyone noticing right away. If someone withdraws collateral at that moment, or the system needs to liquidate a position, the sell order could experience much greater slippage than the oracle reflects.
A collateral shortfall can emerge without any protocol deliberately creating it, simply because the maturity mechanism and the liquidity mechanism aren’t moving at the same pace.
The opposite scenario is also plausible. Most previous PT maturities on Aave have passed smoothly, because risk teams like LlamaRisk and Chaos Labs usually lower borrowing limits and raise safety factors a few weeks before maturity.
PT-AUSD is also tied to a stablecoin with a direct mint-and-redeem mechanism, not a highly volatile asset. Any shortfall, if one occurs, would most likely be just a few percentage points, not a cascading collapse.
What would prove me wrong: if the AUSD pool utilization rate on Aave remains stable after 08/10, with no large positions being liquidated unusually around the maturity date, then the concern in this post will have been just a scenario that never materialized.
Date to watch: 08/10/2026, when PT-AUSD matures on Aave. Monitor the AUSD pool utilization rate in the hours before maturity, and check whether any positions are liquidated around that time.
A question for everyone: when a DeFi protocol accepts an expiring token as collateral, who bears the liquidity risk at the exact moment of maturity — the protocol itself, or the depositors at the back of the queue?
Personal observation, not investment advice