# Supra Dollar Bond (SBO)

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.