# Introduction

### Keystone Finance is the carry coordination layer for Solana.

**How it works:**

* Deposit USDC → mint `ksUSD` at the current share price
* Share price drifts up as carry accrues into the vault
* Carry comes from three sources — Drift SOL-PERP funding, jitoSOL staking yield, USDC lending
* Withdraw any time — instant up to the liquidity buffer, queued beyond

**Architecture:**

* One Anchor program
* One PDA-owned vault
* One share mint (`ksUSD`)
* Three internal modes — **normal basis · reverse basis · idle** — picked automatically by the funding-rate signal

***

## How it earns

Three yield sources that Solana's DeFi ecosystem continuously produces:

| Yield source               | Active when                       | Mechanism                                                         |
| -------------------------- | --------------------------------- | ----------------------------------------------------------------- |
| **Drift SOL-PERP funding** | Normal & reverse basis            | Vault sits on the receive side either way. Delta-neutral in both. |
| **jitoSOL staking yield**  | Normal basis (jitoSOL collateral) | \~5.8% APR embedded in the jitoSOL/SOL rate                       |
| **USDC lending carry**     | Always — buffer, reserve, idle    | Kamino USDC reserve (`lend_idle_usdc` / `lend_reserve`)           |

When funding sits in the dead zone → position closes, the entire NAV runs as USDC lending until the next active regime.

***

## How to use it

```
deposit                  USDC → mint ksUSD at current share price
withdraw_instant         burn ksUSD → USDC from the vault's liquidity buffer
request_withdrawal       burn ksUSD now (locks redemption price), queued for payout
process_withdrawal       permissionless crank — fulfill queued requests in FIFO order
claim_wind_down          (wind-down only) burn ksUSD → pro-rata USDC
```

* Share price (`ksUSD` → USDC) drifts up over time
* Performance fees apply **only above the high-water mark**, at the vault level
* [Fee structure →](/reference/fees.md)

***

## Why Solana

Three primitives must co-locate on one chain:

* **High-yield borrowable LST** — jitoSOL on Kamino (45% LTV at scale)
* **On-chain perp DEX with real bidirectional funding** — Drift Perps (not the borrow-fee LP model used on most EVM perp venues)
* **Sub-cent composability** — Solana's fee model lets the vault switch modes hourly without bleeding gas

Doesn't exist on Ethereum (stETH borrow is capped on Aave) or on EVM L2s (GMX V2 uses borrow-fee, not real funding). **ksUSD is mechanically Solana-only.**

***

## Doc map

**Users:** [Deposit](/keystone-finance/deposit.md) · [Withdraw](/keystone-finance/withdraw.md) · [Check position](/keystone-finance/check-position.md)

**Builders:** [Quick start](/for-developers/quick-start.md) · [Instructions](/for-developers/instructions.md) · [Accounts](/for-developers/accounts.md) · [Events](/for-developers/events.md) · [Errors](/for-developers/errors.md)

**Operators:** [Keeper bot](/for-operators/keeper-bot.md) · [Monitoring](/for-operators/monitoring.md) · [Admin ops](/for-operators/admin-ops.md)

**Reference:** [Whitepaper](/reference/whitepaper.md) · [Historical simulation](/reference/historical-simulation.md) · [Fees](/reference/fees.md) · [NAV & pricing](/reference/nav-calculation.md) · [Security](/reference/security.md) · [Protocols](/reference/protocols.md)

***

## Program

| Network | Program                          | Address                                        |
| ------- | -------------------------------- | ---------------------------------------------- |
| Devnet  | `keystone_finance` (ksUSD vault) | `HvsAc157bJ7Pd4uGr7xssHMifGs6RMbPu14ZMsiEABWT` |
| Mainnet | *new program ID at deploy time*  | Pending audit                                  |


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