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: