⚙️
Documentation - EN
  • 😀Welcome
  • Tutorial
    • How to setup MetaMask wallet
    • How to use SiO2 Finance
  • Basic Functionality
    • Depositing
    • Borrowing
    • Staking
  • Advanced Functionality
    • One-click Flash Loan
    • One-click Short Position
    • Fixed-rate Borrowing
    • Multisig Support
    • WASM Support
  • Systems
    • Interest Rate Model
    • Risk Parameters
    • Safety Module
    • Oracle Price Feeds
  • Tokenomics
    • Allocation and Distribution
    • Governance
  • Development
    • Auditing
    • Contract Addresses
    • Roadmap
Powered by GitBook
On this page
  • FAQ
  • What is utilization rate?
  • What is optimal utilization rate?
  • How is the variable interest rate calculated for each asset?
  • What is deposit APY?
  1. Systems

Interest Rate Model

PreviousSystemsNextRisk Parameters

Last updated 2 years ago

SiO2 Finance's interest rate algorithm is calibrated to manage liquidity risk and optimize utilization. The borrow interest rates are derived from the UUU.

UUU is an indicator of the availability of an asset within the pool. The interest rate model manages liquidity risk in the protocol through user incentives to support liquidity:

  • When capital is available: low interest rates to encourage borrowing.

  • When capital is scarce: high interest rates to encourage repayments of debt and additional supplying.

FAQ

What is utilization rate?

Each asset has a different utilization rate:

U=Borrowtotal/DeposittotalU=Borrow_{total} / Deposit_{total}U=Borrowtotal​/Deposittotal​

As U gets closer to 100%, the asset becomes scarcer. No more liquidity is available at U=100%U=100\%U=100%. This situation can be problematic if depositors wish to withdraw their liquidity with no assets available. However, higher utilization results in higher returns for depositors. Thus, it's important to maximize utilization while protecting the liquidity.

What is optimal utilization rate?

The optimal utilization rate UoptimalU_{optimal}Uoptimal​ is defined to adjust the interest rate for each asset, based on different risk factors. In general, an asset with less liquidity and more volatility has a lower UoptimalU_{optimal}Uoptimal​. This is to change the interest more sharply and at an earlier stage without imposing more risks to the system. See more details at the section below on interest rate calculation.

How is the variable interest rate calculated for each asset?

The interest rate at time ttt (denoted as RtR_tRt​) is defined as follows:

ifU<Uoptimal:Rt=R0+UtUoptimalRslope1if \hspace{1mm} U < U_{optimal}: \hspace{1cm} R_t = R_0 + \frac{U_t}{U_{optimal}} R_{slope_1}ifU<Uoptimal​:Rt​=R0​+Uoptimal​Ut​​Rslope1​​

ifU≥Uoptimal:Rt=R0+Rslope1+Ut−Uoptimal1−UoptimalRslope2if \hspace{1mm} U \geq U_{optimal}: \hspace{1cm} R_t = R_0 + R_{slope_1} + \frac{U_t-U_{optimal}}{1-U_{optimal}}R_{slope_2}ifU≥Uoptimal​:Rt​=R0​+Rslope1​​+1−Uoptimal​Ut​−Uoptimal​​Rslope2​​

Here ​are parameters that are defined below (with R0=0R_0=0R0​=0):

Asset
U_optimal
R_slope1
R_slope2

USDC

90%

0.04

0.60

BUSD

same as above

same as above

same as above

BAI

same as above

same as above

same as above

USDT

same as above

same as above

same as above

DAI

same as above

same as above

same as above

aUSD

same as above

same as above

same as above

WETH

70%

0.08

1.00

WBTC

65%

0.08

1.00

DOT

65%

0.08

1.50

BNB

55%

0.08

1.50

WASTR

55%

0.08

3.00

nASTR

45%

0.08

3.00

To illustrate, here are the interest rates for some assets with different utilization rate:

What is deposit APY?

Dt=UtVt(1−Rt)D_t = U_t V_t(1-R_t)Dt​=Ut​Vt​(1−Rt​)

The borrowing interest paid is distributed as yield for holders deposited in the protocol, except for the share of yields sent to the ecosystem reserve defined by . This interest rate is paid on the asset that is borrowed and then shared among all the liquidity providers. The deposit APY, DtD_tDt​, is:

UtU_tUt​, the

VtV_tVt​, the

RtR_tRt​, the

The average deposit APY over a period also includes any fees incurred, and $SIO2 reward incentives.

Utilisation Rate
utilization rate
variable interest rate
Flash Loan
sToken
Reserve Factor
reserve factor
Interest rates per asset with different utilization rates