Building index-tracking assets on top of options instead of debt

I implemented a physically-settled version of the P/N construction and ran the full cross-party lifecycle on Base.

The variant I tested is for an on-chain pair: WETH/USDC. Since the strike asset exists on-chain, the upside leg can settle by physical exercise: pay USDC, receive WETH.

Mechanism:

  • split 1 WETH into two ERC-20 claims, P and N
  • before maturity, P + N recombine 1:1 back into WETH
  • during the exercise window, N exercises by paying the USDC strike and receiving WETH
  • after the window, P redeems the vault’s remaining balances: collected USDC plus any leftover WETH

Core settlement step:

N + strike USDC -> WETH

settle() does not ask what ETH/USD is. It distributes the assets the vault actually holds.

Live demo run:

  • vault: 0xb1E5f96C7B1eB5792c0a5E659E8917147195f7e1
  • exercise tx: 0x4e818efba541f6a3c7458a10b2e444a8ac0c36424bfdec41b0075e96a556a83e
  • A minted P + N from WETH
  • A transferred N to B
  • B exercised N by paying USDC and receiving WETH
  • C settled the vault
  • A redeemed P and claimed the collected USDC

The exercise tx is the key step: N was burned, USDC moved into the vault, and WETH moved out to the N holder atomically.

For pairs where the strike asset exists on-chain, settlement can be expressed as asset movement rather than price resolution.

The tradeoff is: removing the settlement oracle pushes work into exercise. Price discovery moves to the exerciser’s incentive, off the protocol’s critical path, but someone still has to exercise. I prototyped a keeper that auto-exercises ITM positions and settles, but that is execution infrastructure, not a protocol guarantee.

Open questions I’d value thoughts on:

  • how should P/N secondary liquidity form?
  • how should rolling/rebalancing happen with minimal slippage?
  • can exercise be made reliable at the protocol level without turning settlement back into an oracle problem?

The important part: settlement is an asset transfer, not a price lookup.

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