Supra Dollar

Supra Finance
6 min readMar 30, 2021


Welcome to Supra Dollar — an algorithmic stablecoin running on Binance Smart Chain.

Supra Dollar is an innovative solution that can adjust its supply deterministically to move the price of the token in the direction of a target price to bring programmability and interoperability to DeFi, it is designed by the Supra Finance team as the algorithmic stablecoin on Binance Smart Chain

Starting on April 3rd 00:00 UTC

Inspired by Basis and its predecessors (Empty Set Dollar and bDollar), Supra Dollar is a multi-token protocol that consists of three tokens: SDO (the algorithmic stablecoin), Supra Dollar Shares (or SSO, which holders can claim SDO inflation when the network expands), and Supra Dollar Bonds (or SBO, which can be purchased at 1:1 rate when the network is in contraction and can be redeemed with premium for SDO the network returns to its inflationary state, above the $1 peg).


SDO — Supra Dollar

Supra Dollar (SDO) tokens are designed to be used as a medium of exchange. The built-in stability mechanism in the protocol determistically expands and contracts the SDO supply to maintain SDO’s peg to 1 $BUSD token (which trades closely to a single United States Dollar).


SSO — Supra Dollar Shares

Supra Dollar Shares (SSO) loosely represent the value of the Supra Dollar Protocol and trust in its systemic ability to maintain SDO to peg. During epoch expansions (when TWAP — time-weighted average price of SDO is above the 1 $BUSD peg), the protocol mints SDO and distributes it proportionally to all SSO holders who have staked their tokens in the boardroom.

SSO has a maximum total supply of 21,000 tokens. 1,750 SSO are allocated to treasury. 1,750 SSO are allocated to the team. Both are vested linearly over 12 months. The remaining 17,500 SSO are allocated for incentivizing Liquidity Providers in 4 pools SDO/BNB, SSO/BNB, SSO/BUSD and SSO/USDT with a duration of 12 months.


SBO — Supra Dollar Bonds

Supra Dollar Bonds (SBO) help to incentivize changes in SDO supply during both epoch expansion and contraction periods. For starters, the exchange rate for SDO to SBO is 1:1, but SBO to SDO ratio is dependent upon the mechanism as described below. When SDO’s TWAP falls below 1 $BUSD peg, SBO gets issued and can be bought with SDO at its prevailing price. Doing so takes SDO out of its circulating supply.

Contrary to early algorithmic, seigniorage stablecoin protocols, SBO does not have expiration dates. All holders are able to redeem their SBO for SDO tokens as long as the Treasury has a positive SDO balance, which typically happens when the protocol is in epoch expansion.


  • Epoch duration: 8 hours during expansion and 6 hours during contraction — the protocol reacts faster to stabilize SDO price to peg as compared to other protocols with longer epoch durations.
  • Epoch Expansion: Capped at 6% if there are bonds to be redeemed, 4% if treasury is sufficiently full to meet bond redemption.
  • Bootstrap period: 4 days (12 epochs) goes with full expansion 4% each epoch
  • The protocol keeps 75% of the expanded SDO supply for SSO boardroom stakers for each epoch expansion, 25% toward treasury.
  • First epoch on block 6467360, April 11, 2021 12:00:00


Initially we will offer farming opportunities using the tokens of our partners.

Note: We will use SlimeSwap for all pairs.

Supply: 9000 SDO
Distribution period: 7 days
Start on:
6231600 block | April 3, 2021 0:00:00, UTC

  • Voodoo-BNB
  • Supra-BNB
  • C101-BNB
  • A009-BNB
  • A010-BNB

At the 4th day, our Banks will provide the following pools.

Supply: 91,000 SDO
Distribution period: 10 days
Start on:
6346700 block | April 7, 2021 3:00:00, UTC

  • MDO
  • BDO
  • CRL
  • BTD
  • Cake
  • Alloy

Commencing on day 8, Shares distribution incentivize liquidity provider in 4 pools.

Supply: 17,500 SSO
Distribution period: 12 months
Start on:
6461900 block

  • SDO-BUSD x50
  • SSO-BNB x50
  • SSO-BUSD x50
  • SSO-USDT x50
  • A010-BNB x5
  • SUPRA-BNB x5
  • FLP-BNB x5

SBO (bond tokens) are always on sale, however, a purchase during epoch expansion will result in a net loss. Hence, the platform UI only allows for purchase of SBO when SDO falls below the 1 $BUSD peg.

Bonds start after bootstrap phase, on block 6578840 | April 15, 2021 12:00:00

Early redemption of SBO bonds for SDO (when SDO’s TWAP < 1) will experience a 10% net loss. e.g. if SDO’s TWAP < 1, exchange SBO bonds for SDO will be in a 1:0.9 ratio.

To encourage redemption of SBO bonds for SDO when SDO’s TWAP > 1 and incentivize profit-seekers who are doing bonds. Bonds redemption will be more profitable with a higher SDO TWAP value, of which SBO bonds to SDO ratio will be 1:R, where R can be calculated in the formula as shown below:

R=1.0+min[0.3,(SDO(twapprice)−1.0)∗coeff)]R = 1.0 + min[0.3, (SDO_(twapprice) — 1.0) * coeff)]R=1.0+min[0.3,(SDO(​twapprice)−1.0)∗coeff)]

Where coeff = 0.65

Example 1. if SDO’s TWAP = 1.05,

R = 1.0 + min[0.3, (1.05–1.0)*0.65)] = 1.0 + min[0.3, 0.0325] = 1.0 + 0.0325 = 1.0325

SBO to SDO ratio in Example 1 would be 1:1.0325

Example 2. if SDO’s TWAP = 1.10,

R = 1.0 + min[0.3, (1.1–1.0)*0.65] = 1.0 + min[0.3, 0.065] = 1.0 + 0.065 = 1.065

SBO to SDO ratio in Example 2 would be 1:1.065

As you can tell, SBO holders are able to profit more when they participate in bonds redemption when SDO TWAP >> 1.

Stabilization Mechanism

  • When SDO trades below the $1 target price

When SDO price is below the target price of $1, token holders can purchase Supra Dollar Bonds (SBO) by burning SDO to reduce the circulating supply with a 1:1 ratio, and Bonds will be burnt when users redeem SDO with a premium bonus.

In case of redemption, an amount of SDO will be minted according to the TWAP at the beginning of the epoch (for example, if the SDO price is $1.1 then one Bond burnt will get back 1.1 SDO). Important to note is that Bonds have no expiry after purchase.

  • When SDO trades above the $1 target price

When SDO price is above the 1$ peg, the token supply will have to expand to push it back down to 1$ and the contract will allow the redemption of the SBO.

When the price of SDO continues trading above the $1 target price after bond redemption, the contract mints an appropriate amount of new SDO. This will be distributed to the Boardroom Stakers.

This three token system creates incentives through seigniorage, always pushing SDO towards its peg. SSO is used to redistribute the seigniorage from inflating the asset, while SBO is used to establish a price floor while SDO is in its deflationary state.

  • Epoch Expansion

Capped at +50% of current expansion cap if there are bonds to be redeemed and follows the expansion cap if treasury is sufficiently full to meet bond redemption (See table below for detailed information)

Total SDO Supply Expansion / Bonds Issued per Epoch

  • Under 500k 4.00% Cap
  • 500k+ 3.50% Cap
  • 1m+ 3.00% Cap
  • 2m+ 2.50% Cap
  • 5m+ 2.00% Cap
  • 10m+ 1.50% Cap
  • 20m+ 1.25% Cap
  • 50m+ 1.00% Cap
  • 100m+ 0.75% Cap
  • 200m+ 0.50% Cap
  • 1B+ 0.25% Cap



Supra Finance

Supra is a project for #Defi at #BSC implementing innovative low, medium and high risk investment systems