Minting and redeeming is the exchange of a bAsset for its corresponding mAsset and vice versa.


Each mAsset uses a smart contract to facilitate minting and redemption and hold its collateral.

  • The user sends a bAsset to the mAsset's smart contract.

  • For the USD mAsset, the underlying bAssets could be USDC, USDT, DAI or sUSD pegged crypto assets.

Minting a mAsset offers immediate low slippage conversion of a bAsset into its corresponding mAsset with rates determined by the AMM that work within the bounds defined by hard limits.

All mAssets are ERC20 compliant, non custodial, and redeemable for the underlying bAsset(s) at any time.


In reverse, users redeem their mAssets from the mStable contracts.

  • The user is able to specify which bAsset they wish to receive in return for an equivalent amount of their mAsset (which is then burned, i.e. taken out of circulation).

  • A redemption is valid so long as the given bAsset(s) does not push any of the other bAssets below their minimum weights or over their maximum weights.


The Basic Process of Minting a mAsset

Assume there exists an mAsset called mExample, which has a basket with minimum and maximum weights defined as 5% and 35% for all bAssets respectively. The basket is comprised of 4 underlying bAssets (Assets A, B, C, and D).

To mint a single unit of mExample:

  • Call the smart contract’s mint function;

  • Supply a quantity of bAsset (here, 100 of Asset A).

The smart contract will validate that accepting 100 of Asset A will not push the total quantity of Asset A past its predefined maximum weight of 35% or below the minimum weight 5%.

Asset A is then transferred from the senders address. If the transfer is successful, the smart contract would in turn mint X units of mExample to the specified recipient, where X is computed by the bonding curve.

The user is therefore exchanging their asset for a mAsset of equal or very similar value.

The Basic Process of Redeeming a mAsset

Continuing with mExample, which as before has 4 bAssets and the same weight limits.

To redeem 1000 mExample for a roughly equal amount of the underlying bAsset D:

  • Call the redeem function on the mExample smart contract;

    • Specify that 1000 units of mAsset will be provided for a corresponding amount of Asset D, that is, the redemption asset. The final amount—let's call it Y—will be computed by the bonding curve.

A redemption is only valid if:

  • It does not cause any bAsset to sink below minimum weight or rise above maximum weight.

  • There are a sufficient number Asset D to pay out.

If the redemption is deemed valid, the contract retrieves 1000 mExample, which is burned, and the sender is credited with Y Asset D.

The fee for this single bAsset redemption is equal to the swap fee.

Functionality at weight limits

In the event of one or more of mExample's bAssets being at minimum or maximum weight, minting and redemption options are modified. As before, there are 4 bAssets, minimum weights defined as 5% and maximum weights defined as 35% across them all. In this example, bAssets are at the following weights:

  • Asset A - 35%

  • Asset B - 30%

  • Asset C - 30%

  • Asset D - 5%

A user can always mint or redeem, even at minimum or maximum weight by sending or receiving one or a combination of bAssets that move the basket away from its minimum or maximum weight boundaries.

One way to redeem at max weights is via multi-redemption:

To redeem 100 mExample from the basket via a multi-redemption:

  • Call the multi-redeem function redeemMasset on the mExample smart contract;

  • Specify that 100 of mExample is to be redeemed.

  • Receive 35 units of Asset A, 30 units of Assets B & C, and 5 units of Asset D.

Minting and redemption is analogous for possible future mAssets (e.g. mBTC, mGLD)