Ethereum EIP-8148 draft: custom sweep thresholds

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Ethereum is considering a change that would let compounding validators set how much ETH should remain on a validator before excess rewards enter the network’s automatic withdrawal sweep.

An Aug. 20 edit to draft EIP-8148 lowered the proposal’s minimum custom threshold from 33 ETH to 32 ETH and added a way to set the initial threshold when a new validator is created. If activated, the proposal would let 0x02 validators select a level between 32 ETH and the current 2,048 ETH default. The change would affect reward-sweep timing while Ethereum’s existing exit rules continue to govern principal withdrawals.

Ethereum’s 32 ETH change controls reward-sweep timing

Ethereum currently treats its two execution-address withdrawal credentials differently.

Validators using legacy 0x01 credentials have a 32 ETH effective-balance cap. Any balance above 32 ETH is periodically swept to the withdrawal address, so those rewards stop compounding on the validator.

Compounding 0x02 validators can increase their effective balance in 1 ETH increments up to 2,048 ETH. Under Ethereum’s current withdrawal-credential rules, their balance is automatically swept only after it exceeds 2,048 ETH. Accessing ETH below that level requires a manually requested partial withdrawal.

Validator setup What happens to rewards Automatic sweep threshold
Current 0x01 Excess rewards stop compounding once swept Above 32 ETH
Current 0x02 Rewards compound in 1 ETH effective-balance increments Above 2,048 ETH
Proposed 0x02 Rewards compound until the selected level Custom level from 32 ETH to 2,048 ETH

EIP-8148 would let a new 0x02 validator encode an initial threshold in the deposit that creates it. An absent or invalid custom value would default to 2,048 ETH until a valid post-creation change is processed. Existing compounding validators would also begin at the default and could later submit a valid request.

The draft prevents that setting from becoming an immediate withdrawal tool. A post-creation request must set the threshold at or above the validator’s current balance. If a creating deposit encodes a threshold below the amount deposited, the protocol would ignore it and use the default. A validator seeking a lower level would first have to use the standard partial-withdrawal process.

Once a valid custom threshold is in place, future rewards above it would become eligible for Ethereum’s normal automatic sweep. Principal withdrawals would still use Ethereum’s existing partial-withdrawal or full-exit paths, followed by ordered withdrawal processing.

Infographic comparing current Ethereum 0x01 and 0x02 reward sweeps with draft EIP-8148 custom thresholds from 32 ETH to 2,048 ETH.

Why the stake affected is larger than the validator count

Compounding credentials remain unusual by validator count, yet they already cover a significant amount of ETH.

The latest accessible Pectrified snapshot, dated July 28, counted 16,926 active 0x02 validators. That was 1.91% of active validators, but they held 13.36 million ETH, or 32.43% of active stake.