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Vaults

Sable offers 6 distinct BTC yield strategies deployed as ERC-4626 tokenized vaults on StarkNet. Users deposit WBTC and receive share tokens representing their proportional claim on the vault’s growing assets.

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Vault Catalog

VaultStrategyRiskDescription
Sable SentinelPure Lending1 (Low)Supply WBTC to Vesu PRIME pool. Simplest, safest strategy.
Sable CitadelStaked BTC + Lending2 (Low-Med)WBTC → Endur xWBTC liquid staking → supply to Vesu for dual yield.
Sable TridentRecursive Staking3 (Med)3x recursive WBTC staking loop on Endur for amplified staking rewards.
Sable Delta NeutralBTC-USDC Spread4 (Med-High)Deposit WBTC as collateral → borrow USDC → deploy USDC to yield → earn spread.
Sable TurboUSDC Leverage Loop5 (High)Leverage-loop WBTC collateral on Vesu: deposit → borrow USDC → swap to WBTC → re-deposit.
Sable ApexMulti-Strategy Max Yield5 (High)40% leverage lending + 35% Ekubo LP + 25% Endur staking. Maximum diversified yield.

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ERC-4626 Vault Mechanics

Every Sable vault implements the ERC-4626 tokenized vault standard: 
┌──────────────────────────────────────────────────┐
│                  ERC-4626 VAULT                  │
│                                                  │
│  deposit(assets) ──► mint(shares)                │
│  withdraw(assets) ◄── redeem(shares)             │
│                                                  │
│  share_price = total_assets() / total_supply()   │
│                                                  │
│  As strategy earns yield:                        │
│    total_assets ↑  →  share_price ↑              │
│    Each share redeems for more WBTC over time    │
└──────────────────────────────────────────────────┘

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Core ERC-4626 Functions

  • deposit(assets, receiver) — Deposit WBTC, receive yvBTC shares
  • withdraw(assets, receiver, owner) — Burn shares, receive WBTC
  • total_assets() — Returns total WBTC managed (deployed + idle)
  • convert_to_shares(assets) / convert_to_assets(shares) — Conversion helpers

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Deposit Flow

1

Approve WBTC

User approves the vault contract to spend WBTC tokens.
WBTC.approve(vault_address, deposit_amount)
2

Deposit to Vault

Call vault.deposit() to mint yvBTC shares.
vault.deposit(amount, receiver)
Vault mints share tokens to receiver based on current share price.
3

Curator Deploys Idle Funds

The curator calls deploy_idle() via the /api/curator endpoint to deploy WBTC into the strategy.
Idle WBTC sitting in the vault does not earn yield until deployed by the curator.

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Withdraw Flow

1

Request Withdrawal

User calls vault.withdraw() specifying the amount of WBTC to receive.
vault.withdraw(wbtc_amount, receiver, owner)
2

Strategy Unwind

Vault automatically unwinds positions to free up WBTC:
  • Sentinel: Withdraw from Vesu PRIME
  • Citadel: Unstake xWBTC, swap to WBTC
  • Trident: Unwind recursive loop (may use flash loans)
  • Delta Neutral: Repay USDC debt, withdraw collateral
  • Turbo: Unwind leverage loop via flash loan
  • Apex: Exit LP, unstake, repay debt atomically
3

Receive WBTC

WBTC is transferred to receiver, share tokens are burned.

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Curator Pattern

The curator (contract owner) manages strategy execution. Idle WBTC is deployed to yield protocols via: 
// API endpoint: /api/curator
POST /api/curator
{
  "vault_id": "sentinel",
  "action": "deploy_idle"
}

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Deployment Strategies by Vault

Pure Vesu PRIME Lending
  1. Read idle WBTC balance
  2. Supply WBTC to Vesu PRIME pool
  3. Earn supply APY + BTCFi STRK rewards
Contract: 0x04ec7fdb1679450fb88eae9facc439a46be4ddeba628211e269a7467f6e0971b

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Income Streams

SourceVaults Using ItDescription
Vesu Lending APYSentinel, Citadel, Trident, Turbo, ApexInterest from borrowers on Vesu
Endur xWBTC StakingCitadel, Trident, ApexLiquid staking yield on BTC
BTCFi Season STRKAll100M STRK incentive program rewards
Ekubo LP FeesApexConcentrated liquidity market making fees
Borrowing SpreadDelta Neutral, TurboEarn more on deployed capital than borrowing cost
Leverage AmplificationTrident, TurboMultiply base yield via recursive positions

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Share Price Growth

The share price increases as yield accrues: 
Example: Sentinel Vault
  Initial deposit: 1.0 WBTC → 1.0 yvBTC (share price = 1.0)
  
  After 30 days at 8% APY:
  Total assets: 1.00657 WBTC
  Share price: 1.00657 WBTC per yvBTC
  
  Redeem 1.0 yvBTC → receive 1.00657 WBTC
  Profit: 0.00657 WBTC

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Vault Contracts

Sentinel

Pure WBTC lending on Vesu PRIME. Lowest risk, steady yield.

Citadel

Staked BTC + lending. Dual yield from Endur staking and Vesu.

Trident

3x recursive staking loop. Amplified staking rewards.

Delta Neutral

BTC-USDC spread strategy. Earn yield delta between USDC and borrowing.

Turbo

USDC leverage loop. High risk, maximum leverage.

Apex

Multi-strategy diversification. 3-way split for maximum yield.

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Flash Loan Unwind

Complex strategies (Turbo, Trident, Apex) may require flash loans for withdrawal: 
Withdrawal Flow with Flash Loan:
  1. Borrow WBTC via flash loan
  2. Repay all debt positions
  3. Withdraw collateral from protocols
  4. Repay flash loan
  5. Return remaining WBTC to user
  
  ✓ Atomic — no partial state
  ✓ No user funds at risk
Flash loan withdrawals may fail in extreme market conditions (low DEX liquidity, high borrow rates). Always monitor your position health.

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Risk Levels

Vaults: Sentinel, Citadel
  • No leverage or low leverage
  • Simple, battle-tested strategies
  • Lower APY, higher safety
  • Recommended for risk-averse users

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Next Steps

Deposit into a Vault

Step-by-step guide to your first vault deposit

Understanding APY

Learn how vault APY is calculated

Vault Contracts

Technical documentation for each vault

Risk Management

Best practices for vault safety

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