0xAssets

Overview

0xAssets (0x) are the protocol’s base-denominated ERC-20s (18 decimals) that abstract a collateral family (e.g., 0xBTC for the BTC family, 0xETH for the ETH family). Each UCE instance manages exactly one 0x (its family base) and treats all supported underlyings in that family (e.g., WBTC/cbBTC for BTC; WETH/stETH-like wrappers for ETH) as A (underlying asset) against that 0x. A yield wrapper of an 0x (e.g., s0xBTC, s0xETH) is an ERC-4626 vault (s0x asset) whose asset() is the 0x itself.

Key properties

• ERC-20, 18 decimals, upgrade-safe minter/burner: 0x has fixed 18-dec precision; UCE is the sole minter/burner/settler.

• Deterministic pair gating: Only four swap planes exist: A↔0x and 0x↔s0x. There is no A↔A or 0x↔0x path.

• No oracle on redemption (0x→A): Redemption is a pure decimals normalization (0x 18-dec → A native decimals), minus a dynamic redemption fee that decays over time and bumps on usage.

• Oracle on mint (A→0x): Minting 0x from A uses Chainlink-style feeds (base or USD + base/USD) and applies an optional mint haircut (bps). Results are then reduced by optional tin (mint-side fee) that mints 0x to treasury.

• Inventory semantics: 0x on UCE can be (i) unreserved (protocol inventory) or (ii) reserved for allocators (per-allocator reservedZeroX). Referral mints must settle from the referrer’s reserved inventory.

• Backed by custody & pockets: Underlyings are held partly on UCE (per-asset reserve slice) and mostly in pockets (global or allocator-specific custody/vaults) with allowance-bounded pulls.

Examples

• 0xBTC instance (family = BTC):

  • Underlying Asset (A): WBTC, cbBTC, …

  • 0x: 0xBTC (18-dec).

  • s0x asset: s0xBTC (ERC-4626 with asset() == 0xBTC).

  • A→0x path: WBTC → 0xBTC uses BTC-base pricing (WBTC/BTC or WBTC/USD + BTC/USD), optional haircut, tin to treasury.

  • 0x→A path: 0xBTC → WBTC is decimals-only scaling, minus dynamic redemption fee (in WBTC).

• 0xETH instance (family = ETH):

  • Underlying Asset (A): WETH, staked ETH variants mapped via policy.

  • 0x: 0xETH (18-dec).

  • s0x asset: s0xETH (ERC-4626 with asset() == 0xETH).

  • A→0x path: WETH → 0xETH via ETH-base pricing, optional haircut, tin.

  • 0x→A path: 0xETH → WETH via decimals-only scaling, minus redemption fee (in WETH).

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Mechanics & Policy (applies to 0xBTC/0xETH)

• Swaps

  • A→0x: Pull A; retain per-asset reserveBps n UCE; deposit remainder to the selected pocket (allocator’s pocket on referral, otherwise global). $Quote = oracle price × decimalsNormalization × (1 − haircut)$. Tin (bps) is taken in 0x and minted to treasury. Settlement source for 0x out:

    • Referral: must use referrer’s reservedZeroX (reverts if insufficient).

    • No referral: unreserved protocol 0x → pro-rata draw from allocators’ available capacity (nets down their debt) → mint any shortfall.

  • 0x→A: Pull 0x to UCE; compute snapshot redemption fee rate; deliver exact A using on-hand reserve first, then allowance-bounded pocket withdrawal (referral pocket when present, else global). Fee is transferred in A to treasury; post-settlement the rate bumps by redeemed fraction and decays multiplicatively over time.

  • 0x↔s0x: Pure ERC-4626 accounting: deposit/redeem/convertToShares/convertToAssets with no oracle use; no protocol fee on these legs.

• Decimals discipline

  • 0x is always 18 decimals. Conversions 0x↔A use integer scaling with cached token decimals; previews mirror execution.

• Risk knobs

  • Per-asset reserveBps: Higher improves immediate redemption capacity in that A; lower increases yield reliance on pockets.

  • Tin (mint fee) & Mint Haircut: Tin monetizes A-side issuance to treasury; haircut provides oracle-side safety margin on A→0x.

  • Per-asset pause & oracle heartbeat: Any leg for a paused asset reverts; stale/invalid oracle reverts A→0x.

• Allocator coupling (referrals)

  • Referral routes A to the allocator’s pocket and requires 0x delivery from that allocator’s reservedZeroX.

  • Non-referred flow can socialize via pro-rata 0x draw, which reduces allocators’ debts in index-consistent fashion.

• Invariants (intuitive)

  • No synthetic A minting: A delivered is strictly bounded by on-hand + allowance-bounded pocket liquidity.

  • Preview parity on redemption: Snapshot fee ensures A out matches preview (absent external state changes).

  • Index-consistent debt: All allocator debt changes occur in base units and scale by global debtIndex; pro-rata 0x draws net debt down fairly.

Takeaway: 0xBTC and 0xETH are the family bases that make collateral fungible inside their domain, with oracle-guarded minting, oracle-free redemption, allocator-exact referral routing, and deterministic settlement bounded by custody reality.