Why we like Balancer

Andy Singleton
Published in
2 min readJan 4, 2024

We just moved SWEEP/USDC AMMs to Balancer. The Balancer metastable swap is exactly what we need to maintain the SWEEP peg, while still paying returns and getting price signals.

Swap for SWEEP using Balancer
On Arbitrum
On Ethereum
On Optimism
On Base
On Avalanche
On Polygon

We put AMMs at the center of Sweep Protocol. AMMs are the storefront where users and software can buy and redeem SWEEP. They should deliver enough of a price signal to drive minting, redeeming, and moving money between chains. And yet, they should have a mostly stable rate that doesn’t require LPs to hold a big pool of expensive, non-invested dollars.

It’s stable

Our Balancer pools use a stable price curve that keeps SWEEP close to the target price even for large trades. It should hit the target price exactly when the value of USDx and the value of SWEEP are balanced in the AMM. If the pool has more USDx, or more SWEEP, the price moves enough to provide signals for minting, redeeming, and moving money.

And yet, metastable

However, the SWEEP price is not really stable. It has a target price that moves a little bit every day as it earns interest. The Balancer “metastable” pool tracks moves in the target price or “rate”. It makes a call to retrieve the target price, and if the target price moves, the price in a balanced AMM also moves.

We could not get this effect with concentrated liquidity AMMs like Uniswap V3. When the target price moves in a CL AMM, the AMM price does not. A concentrated liquidity AMM requires us to buy all of the positions between the current price, and the new target price.

It’s a good market for Balancer

Metastable swaps are appropriate for pairs like <Eth>/<staked-ETH> and <USD stable>/<USD interest earning>. In both cases, the interest-earning side crawls about 5% per year. Those are big categories.

We have a special request for the Balancer team. They removed the historical price oracle from the most recent release. We’d like to get it back. Prices from the current block are easy to manipulate with flash loans. The historical price oracle returns an average of prices from past blocks, which is MUCH harder to manipulate. This price is useful in Sweep for operations like setting an interest rate, and allowing minting.

It’s a plugin

We deploy an AMM Plugin contract on each blockchain that links Sweep to a local SWEEP/USDx AMM. We can use Balancer on the blockchains where Balancer is available. Otherwise, we can use a different local AMM.

Thanks, Balancer.


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Andy Singleton

Software entrepreneur/engineer. Building DeFi banking at Maxos — https://maxos.finance . Previously started Assembla, PowerSteering Software, SNL Financial.