Fees

EthAnchor is scheduled for deprecation and is to be replaced with xAnchor. It is highly recommended that new integrations are built with xAnchor and not with EthAnchor.

EthAnchor is built using various blockchain infrastructure that charges fees on their usage. Using EthAnchor incurs fees that are calculated based on the deposit / redeem amount. Fees listed at this section are applied independent of gas spent on Ethereum transactions.

Operation	# of Swap Fees	# of Shuttle Fees	# of Terra Tax
Deposit	Once	Once	Once
Withdraw (Redeem)	Once	Once	Twice

Swap Fees

Operations with non-UST stablecoins are automatically converted to UST via Curve. A 0.04% fee is applied by Curve on each swap.

In addition to Curve fees, the swap will incur slippage -- the difference between the current market price and the price at which the trade is effectively executed.

Shuttle Fees

Shuttle ignores transfer requests with a transfer value smaller than 1 UST.

Cross-chain transfers of Terra stablecoins and aTerra tokens between Ethereum and Terra are facilitated with the use of Shuttle. Shuttle charges a fee only for cross-chain token transfers from Terra to Ethereum, with the fee amount being:

$$\text{shuttleFee(transferAmount)}=\text{max} (1\,\text{UST},\,\text{transferAmount} \cdot 0.25\% )$$

0.25% of the transfer amount is charged as Shuttle fees, decreasing with the transfer amount until the fee reaches the 1 UST minimum. Amount received after fees will be:

$$\text{receiveAmount} = \text{transferAmount}-\text{shuttleFee}(\text{transferAmount})$$

Note that this fee will be applied once for both deposits and withdrawals.

Terra Blockchain Tax

Terra stablecoin transfers that occur on the Terra blockchain require tax (protocol fee) to be paid. Tax amount is dependent on the transfer amount, represented as:

$$\text{terraTax(transferAmount)} = {\text{min}(\text{taxCap}, \text{transferAmount}\cdot\text{taxRate})}$$

Tax amount increases as the transfer amount increases, until it reaches a cap of 1 TerraSDR (SDT), currently valued at around ~1.42 UST. Terra SDR is a Terra stablecoin pegged to the International Monetary Fund's Special Drawing Rights (SDR) and its value -- along with the tax cap -- may differ as exchange rates vary with time.

EthAnchor is configured to automatically deduct the amount of stablecoins required for tax before making Terra-side transfers. Thus the post-transfer receive amount will be:

$$\text{receiveAmount} = \text{transferAmount} - \text{terraTax(receiveAmount)}$$

Note that this tax fee is applied once for deposits and twice for withdrawals.