2. The Reserve

The GoodDollar Reserve is the smart contract that governs the vault holding the assets that back G$ tokens. The algorithm that guides the reserve is based on the Bancor formula, which has been altered to fit GoodDollar’s needs. There are two important characteristics unique to the GoodDollar Reserve:

1. The reserve supports the generation of G$. Users can always convert to and from G$ via the reserve.

2. The unique math of the GoodDollar Reserve lends G$ exceptional stability.

Key Terms

Reserve: The pool of tokens backing G$ generation.

Reserve Ratio (Rr): The ratio between the total G$ market cap and the value of the reserve.

Supply (S): The current circulating supply of G$.

Price (P): The price of G$ relative to the tokens in reserve.

Exit Contribution: A contribution paid when selling G$ into the reserve in exchange for another currency.

G$X: A token earned as a reward for buying G$ from the reserve that can be used to reduce a user’s exit contribution in a subsequent sale of G$.

The Reserve Ratio (Rr)

The ratio between the value of the reserve and the market capitalization of G$. The lower the ratio, the more G$ the protocol can generate.

Reserve Functions:

The GoodDollar Reserve performs three different functions important to the GoodDollar Economy: Expansion; Conversion; Interest Deposits. These are outlined below (for more on the underlying math, please see the appendix of the GoodDollar white paper).

• Expansion is the pre-set annual rate by which the token supply increases, thereby reducing the reserve ratio. For instance, if the expansion rate is set to 10% annually and the year begins with a reserve ratio of 1, then by the end of the first year the reserve ratio would be 0.9, by the end of year two, 0.81, and so on (Equation 3).

• Conversion is the process that enables users to exchange G$ for CDAI and vice versa. Since the GoodDollar Reserve is essentially an automated market maker (AMM) that works on a bonding curve, the amount of G$ minted or burned depends upon how much collateral is added or removed from the reserve. Users who buy G$ receive a matching number of G$X tokens as a reward for their purchases, which can be used to reduce their exit contributions when they choose to sell G$ (see below).

• Interest deposits into the GoodDollar Reserve from a third-party protocol are converted to G$ in a different way than during the crypto exchange process outlined above. When a user buys G$ from the GoodDollar Reserve in exchange for a supported currency, new tokens are minted and the price of G$ rises. In contrast, when a user deposits interest, there are more tokens minted, but the price of G$ doesn’t change.

Exit Contributions

G$X Tokens

In addition to the G$ coin and the GOOD governance token, the GoodDollar ecosystem includes a third type of crypto token: G$X. Members who hold G$X tokens can use these to reduce their exit contributions when selling G$ to the reserve by an amount set by the DAO. Users acquire G$X tokens as a reward for buying G$ from the reserve (currently, a user who buys 100 G$ will also receive 100 G$X).

Exit contribution calculation including G$X

1. Discount = 1 - G$X/G$sold

   1. If Discount <= 0 Then Discount = 0

2. Exit contribution = Setcontribution*Discount

G$X Supply & Burn policies

For every G$ token bought from the GoodDollar Reserve, the reserve will issue 1 G$X token. For every G$ token sold to the GoodDollar Reserve, the reserve will burn 1 G$X token.

Stability

As described above, the impact of buying and selling currencies to and from the GoodDollar Reserve depends on three factors:

1. The size of the reserve ratio.

2. The size of each transaction.

3. The total reserve value.

Simulator

A Price similator with dynamic reseerve rate function is available here :

Helper contracts

Helper contracts are smart contracts that connect the GoodDollar Reserve to other liquidity networks in order to allow liquidity to flow from G$ to any other token that has an automated market maker (AMM). For example, if a user wants to convert token X to G$, the helper contract will first convert token X to DAI using Uniswap, and then convert DAI to CDAI using Compound. Finally, it will convert the CDAI to G$ using the GoodDollar Reserve. Future versions of the protocol may extend this functionality to additional protocols, such as Bancor and Aave.