What Happens When Pendle PTs Expire?

At midnight UTC on the date in its name, a Pendle principal token stops earning and starts redeeming. One PT becomes one unit of the asset it was priced in. Its twin, the YT, collects the yield the underlying earns, and at expiry it is worth nothing. That is the entire event. Nothing is sent anywhere, nothing is sold, and nothing is closed. The token stays exactly where it was, in a wallet, inside a pool, or posted as collateral, worth par, until somebody redeems it. Exiting is on you, and exiting at expiry is what the design expects.

Almost everybody redeems on time, but there is still real money on chain in the form of expired PTs. We read every Pendle market ever deployed on Ethereum mainnet: $25.4 billion of PT has reached its date and 99.8% of it was redeemed. The unredeemed $42 million is still sitting there, redeemable at par every block, and it is not dust. One wallet holds $905,000 of PT-USDe that matured on September 25, 2025 and has not moved in 348 days. $1.2 million of PT-weETH from June 27, 2024 is still outstanding, and half of it belongs to liquidity providers who never pulled their position out of the pool. $14 million of PT sits inside 172 expired pools that nobody withdrew from. Every figure here is as of September 8, 2026. We first read them on September 3, 2026, and the largest position in that first count moved while we were writing.

Expiry is a timestamp that the market and the yield token both check. When it passes, four things change and one does not.

Minting stops. mintPY carries a notExpired guard, so no new PT or YT can be created from the underlying.

Trading stops. The market's swap functions carry the same guard and revert with MarketExpired. Price discovery is over because there is nothing left to discover: a PT is worth one unit, full stop.

The yield token goes to zero. On the first transaction after expiry the YT records the underlying's index as firstPYIndex and stops accruing to holders. YT holders can still claim what they earned before the date, and nothing after it.

Redemption opens. Before expiry, redeeming needs a matched PT and YT. After it, redeemPY burns PT alone and returns the underlying, and the market's burn still works, which is how a liquidity provider gets PT and SY back out of a pool.

What does not change is the position. The contract keeps no list of holders to pay, has no sweep, and has no expiry handler. A PT is an ERC-20 that happens to have a date in its symbol that communicates at which point redemption can occur. Redemption is a call the holder makes, or nobody does.

And there is a cost to not making it. The yielding asset underlying the PT keeps earning after the date, and that yield is not yours. When a matured PT is finally redeemed, the contract hands back exactly one unit of the underlying at that moment and books everything the underlying earned since the date, syInterestPostExpiry, to Pendle's treasury. Pendle's fee page says it without hedging: all yield and points generated by unredeemed, matured positions are automatically redirected to the Pendle treasury fee wallet, and the stated purpose is to incentivize users to promptly redeem and roll over. So a PT that sits keeps its face value and gives its yield to the protocol, every day, until someone exits it.

Pendle has deployed 487 markets on mainnet and 442 of them have expired. For each expired PT we read the token's supply at the last block before its date and its supply as of September 8, 2026. Supply only leaves through redemption, so the gap is the money that followed the design out.

$25.4 billion reached its date and 99.8% of it was redeemed. That is not luck. It is savvy operators following the design: the date arrives, the position is closed, the capital moves on. The biggest tranches are the cleanest because the biggest positions are run by people who watch them: September 25, 2025 matured $5.7 billion, and 99.95% of it exited. The market is telling us what the money wants to do at expiry. It wants out.

The largest position in our September 3 count was a Safe holding $12.6 million of PT-STRCx-27AUG2026, 87% of everything that market had outstanding when it matured. It is also the clearest example in the data of the behavior Pendle designed for, because a few hours after we counted it, it was gone.

The operator wanted to be in the November market and said so on chain. On expiry day itself it claimed its pool rewards and bought its first November PT. Then it left the matured position alone for a week: redeemable at par, earning nothing, its yield flowing to Pendle's treasury. On September 3, 2026 it redeemed the whole thing in one transaction, and eleven minutes later it was buying November, tens of thousands of PT through the night and more every day since. By September 8 it held 78% of the November market. That is the desired behavior, redeem and roll and keep the capital working, from an operator who clearly knew what it wanted and was holding eight figures. And it still sat for a week. If the most attentive holder in the count was a week late, the wallet that has sat for 348 days is not a different kind of holder. It is the same behavior without the follow-through.

Group every expired PT by how long ago it matured and the curve is not a slope. It is a cliff, a shelf, and a floor.

Ninety-five percent goes home in the first month. What is left barely moves for the next two, and almost half of that shelf is one depegged asset, msUSD, whose PTs return 63 cents on the dollar, so nobody redeems them. Past ninety days the outstanding share is a tenth of a percent, and it takes another year to halve. Below ninety days a holder is late. Above it a holder is gone.

We named every holder of every expired PT above $1,000. Contract names, Safe singletons and Pendle's own contract sets sort them, and everything left is a wallet.

Three quarters of it is in two places: plain wallets, and the Pendle pools themselves. The money-market slice is the leveraged case, collateral that stopped earning while the loan against it kept charging, and we covered it in A Problem We Accepted for Years, Solved in a Week. Everything else has nothing owed against it.

Wallets are the long tail. About a thousand of them hold more than $100 of expired PT, another two thousand hold dust, and the ten largest hold nearly half of the $17.6 million between them. The pool line is different in kind. That $14 million never became anybody's PT. It is the PT half of LP positions in 172 expired pools, and 98 of those pools still hold at least half of their PT's entire supply. An LP token does not show a date, does not show a PT, and after expiry does not change at all. It just stops paying.

So the unredeemed PT takes three shapes, and each is a different number of steps from home. PT in a wallet is one call. PT inside a pool is a burn and then a call. PT under a loan is a repayment first.

Not every PT redeems for what it promised. A PT is a claim on one unit of its underlying, and if the underlying lost its peg, that claim is on a dollar that redeems at a discount. Priced as of September 8, 2026: msUSD trades at 63 cents, so its two PTs promise $13.6 million and return $8.6 million. A few others lost value after expiry because the underlying fell while the redemption index stayed frozen: jrUSDat returns 48 cents on the dollar, vyUSD and yUSD return 88, and csUSDL returns nothing.

That is the whole list, and it is $5 million of promised value out of $42 million. The other $33 million redeems for exactly what it promised, and even the depegged pile is $8.8 million of real money that a redemption returns as of our analysis. The mechanics hold too. On September 3, 2026 every one of the 442 expired PTs was fully backed at the Pendle layer, and a simulated liquidity provider leaving each of the 174 expired pools above $1,000 exited cleanly from 172 of them, the two failures holding $5,000 between them. The money is not trapped. It is unclaimed.

Nothing about the design says it should be otherwise.

The date lives in the token symbol and nowhere else. No event fires at expiry, no balance changes, and no notification exists on chain. A redeemable PT makes no noise, and because it keeps its face value there is no loss to notice either. A liquidation is loud. A matured PT is silent.

The interface agrees. Pendle's app moves an expired market to an inactive list and shows a redeem button to anyone who navigates there. That reaches the people who were going to redeem anyway, which is what the curve looks like: the first month catches the people watching, the next two catch the people who got a reminder, and after that the remainder belongs to wallets nobody opens.

The position is often not a PT at all from where the holder stands. It is an LP token, or a Penpie or Equilibria wrapper around one, or collateral on Morpho, and each of those needs its own steps before redeemPY is even the right call. Safes and smart accounts have to sign for themselves. And the markets come from five factory generations, so the exit for one is not the exit for all.

Then the calendar keeps going.

Half a billion dollars of PT matures on mainnet between September 8, 2026 and January. If the curve holds, about five percent of every tranche will still be sitting a month after its date.

A reminder does not reach the wallet nobody opens. Neither does an intent that names a market, because the position nobody remembers is the one nobody pointed an intent at.

The Generalized Expired Pendle Exit leaves the market as a typed hole the solver fills at execution. Signed once, it asks each of Pendle's five factory generations whether it deployed the market the wallet holds, requires isExpired, claims any rewards owed, and branches on what it finds: LP is removed, PT is redeemed, SY is unwrapped, and the underlying comes back to the wallet, earning again on the next block. It runs on a schedule, so it sweeps after every tranche, on the wallet you use and the ones you stopped using. Nothing is custodied and no key changes hands. The permission covers exactly the exit it names.

For a position you already know about and want to steer, six narrower plugs sit on top of the sweep.

Twenty-five billion dollars reached its date and $42 million of it is still waiting on a call that nobody has a reason to remember. The design asks one thing of you at maturity: exit. Sign the exit once, on the wallet you use and the ones you stopped using, and let the plug handle the rest.