> For the complete documentation index, see [llms.txt](https://cheomayield.gitbook.io/cheomayield-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cheomayield.gitbook.io/cheomayield-docs/architecture.md).

# Architecture

## Yield engines

CheomaYield runs **its own proprietary yield engines**. The settlement chain is not where yield is sourced — yield comes from two strategy sleeves *inside* the vaults:

1. **GCC sukuk bonds (core, \~99%)** — sovereign and corporate bonds from UAE, KSA, Qatar, Kuwait, Bahrain, and Oman. This is the stable, low-volatility base.
2. **Cross-venue prediction-market straddle (satellite, \~1%)** — market-neutral straddles on event contracts, both sides booked, profiting from volatility rather than direction.

The sustainable design target is \~13% APR. Promotional campaign vaults (Wave 1, partner vaults) advertise higher fixed rates on small, time-bounded caps.

## Vault types

### `CheomaPreDeposit` — fixed-APY tokenized vault

* Fixed, immutable `apyBps` set at deploy.
* Deposits mint a non-transferable (soulbound) ERC-20 receipt.
* Principal tracked in per-deposit FIFO lots with a 90-day lock.
* Interest accrues deterministically on-chain (`block.timestamp`), no backend write, no front-run window.
* `setCap`, `setDepositsOpen`, `setWithdrawalsOpen` are admin-controlled.

### `PartnerPreDeposit` — bond-gated vault

* Extends the pre-deposit vault with a **partner-token bond gate**: to deposit, a user must hold ≥ `minGateUsd` worth of a partner token, escrowed into the vault until full withdrawal.
* Partner token price read from a 30-minute Uniswap V3 TWAP.
* Used for co-branded partner communities (e.g. GIWA Markets).

### `CheomaVault` — shares-based combined vault

* The original vault: deposits mint shares (no transferable token), operator-managed yield.
* Used for the testnet "Combined Vault" (99% sukuk / 1% straddle).

## Custody model

Every vault uses a two-key split:

* **`admin` (HOT)** — configuration only (`setCap`, open/close deposits & withdrawals). Cannot move funds.
* **`treasury` (COLD)** — the *only* role that can move funds out (`withdraw`, `emergencyWithdrawAll`). Held offline by the operator.


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