Across protocol

Across protocol rewards are changing as ACX emissions wind down

Updated August 2026

Across protocol rewards are a two-part liquidity-provider return: fees from crosschain pool use and, historically, ACX emissions distributed through reward locking. The fee layer remains part of the operating bridge. The ACX token is being wound down during the protocol's corporate transition, so old emission rates, yield screenshots, and multiplier projections should not be read as live offers.

This page isolates the reward mechanism: how utilization fed fee income, how governance adjusted ACX subsidies, and how claims changed loyalty multipliers. It also separates durable rules from expired rates.

The short version: They are liquidity-provider incentives combining utilization-based pool fees with ACX emissions; compare fee income with each pool's token subsidy.

Do not combine pool APY and rewards APY

The most common reading error was adding a displayed pool rate to an ACX rate without separating their denominations, clocks, and control mechanisms. Pool APY represented fee income in the deposited asset. Rewards APY represented an ACX subsidy from a separate distributor. A combined percentage concealed the source of each return.

Across liquidity providers supplied assets to the HubPool on Ethereum and received LP tokens representing their share. Bridge activity generated fees when capital supported crosschain rebalancing. The Accelerating Distributor then issued ACX to eligible staked LP tokens under pool-specific parameters. ETH or WETH fee income therefore behaved differently from an ACX balance, while USDC, USDT, DAI, and WBTC positions carried their own asset exposure. A dollar-denominated total also moved when either the pool asset or ACX changed market value.

Read the fee component in pool units, the subsidy in ACX units, and the Ethereum transaction costs separately. That split remains useful even while ACX emissions wind down, because fee income belongs to the live bridge mechanism.

How does pool utilization change Across LP fees?

From there, Across LP fees rise along an Aave-style two-slope curve as a route consumes more available liquidity and approaches its configured utilization kink. Low use sits on the shallow segment. Use above the kink enters the steeper segment, raising the charge for capital that is harder to rebalance.

The curve takes utilization U from 0 to 1, a kink value, a base rate R0, a below-kink slope R1, and an above-kink slope R2. Those four rate parameters are set per token and route, so a USDC movement from Arbitrum to Base need not price like a USDC movement from Ethereum to Optimism. The annualized curve is converted to a weekly rate with 52 periods before the transaction amount is applied.

Relayer repayment location provides the decisive exception. An LP fee is 0 when the relayer takes repayment on the origin chain because no crosschain pool rebalancing is required. A different repayment chain creates the rebalancing demand that the utilization curve prices. This fee path operates independently from ACX.

ACX emissions answered a different demand signal

The ACX subsidy was governed separately from transaction fees, using pool utilization and comparable bridge yields to decide whether base emissions should move. The ACX Emissions Committee did not set the pool fee curve. It adjusted the number of reward tokens assigned to an eligible asset pool.

Its framework used two rolling inputs. One was each asset's 7-day average Across utilization. The other was a 7-day, total-value-weighted Yield Index built from comparable pools on Stargate, Hop, and Synapse. ETH, USDC, USDT, and DAI fell within that committee framework, while WBTC and ACX required separate governance treatment because the comparison set was not equivalent. These distinctions stopped a low-demand pool from receiving the same subsidy logic as a heavily used one.

Utilization therefore influenced both layers through different paths. Higher use lifted the fee curve directly, while the committee read sustained utilization as evidence for retaining or adjusting ACX support. Neither historical emission totals nor an old APY card establishes a current subsidy during the ACX wind-down.

The four utilization bands constrained committee action

The governance framework divided utilization into four bands, then permitted a 25% emission change followed by 14 days without another adjustment for that asset. This cadence limited each decision and gave liquidity time to respond before the next review.

The bands were 0%-25%, 25%-50%, 50%-75%, and 75%-100%, each paired with relative-yield triggers. Both utilization and the Yield Index used 7-day averages, so a single busy block or quiet hour did not set the committee response.

In the lowest band, a relative yield at or above -50% could trigger a 25% decrease, while a reading at or below -95% could trigger an increase. The next three bands used decrease triggers of +25%, +50%, and +100%. Their increase triggers were -75%, -50%, and -25%, respectively. The thresholds demanded progressively stronger fee income as utilization rose, because a busier pool had more reason to retain capital.

Between those trigger lines, emissions stayed unchanged.

These numbers describe the approved emissions framework, not an immutable smart-contract formula or a present ACX quote. The committee applied the framework to base emissions, while Across DAO governance handled assets outside its mandate. During the token wind-down, the same bands remain valuable for interpreting earlier reward decisions and separating them from pool-fee economics.

Reward locking changed each holder's share

Reward locking increased an LP's individual ACX earning rate over time, while the pool's base emission remained shared pro rata among staked positions. Risk Labs implemented the mechanism through the Accelerating Distributor, which tracked the stake and a wallet-specific multiplier for each enabled LP token.

Under the revised configuration, the multiplier began at 1x on day 0 and rose linearly toward 2x after 100 days without a claim. That path placed the day-25 checkpoint at 1.25x, day 50 at 1.5x, and day 75 at 1.75x. The 2x ceiling changed the rate applied to a position; it did not double the pool's base emission. Any reward claim reset the wallet's multiplier to 1x, so accrued ACX and the future earning rate belonged to one timing decision. A second page describes it Inside protocol.

Pool dilution mattered as much as the multiplier

An LP's ACX allocation depended on both the personal multiplier and the wallet's share of all eligible, staked LP tokens in that pool. New deposits enlarged the denominator, so a 2x position still earned fewer tokens when much more liquidity joined. A base-emission cut reduced every participant's starting allocation, while a higher pool fee could partly offset that change in the deposited asset. Position size, total staked supply, multiplier, and base emission jointly determined the ACX output.

Circle CCTP changed the utilization input

Circle's Cross-Chain Transfer Protocol lowered the USDC liquidity burden by rebalancing native USDC more efficiently, weakening the case for a large token subsidy. Across could move USDC between supported environments without relying only on slower canonical bridge paths, so the HubPool needed less idle liquidity for the same operational purpose.

That structural change matters because utilization is a ratio, not a raw transfer count. If capital requirements fall while deposited liquidity stays high, the measured utilization falls even when users continue bridging. The fee curve then prices less scarcity, and the emissions framework reads weaker demand for subsidized capital. The ACX Emissions Committee added the 0%-25% band to address precisely this mismatch. Circle CCTP therefore affected rewards through the denominator and the rebalancing process, not by changing an LP's loyalty multiplier.

Lower utilization reduced both fee pressure and the economic case for ACX support.

Claims created an irreversible timing choice

A reward claim crystallized accrued ACX and reset the legacy loyalty multiplier, so claim timing changed subsequent emissions without changing the LP balance. ACX is an ERC-20 token with 18 decimal places, and claiming required an Ethereum transaction. The on-chain amount was distinct from the pool asset and its fee accrual. Rebuilding from 1x to 2x then required another 100 claim-free days, joining gas cost and lost acceleration in one decision.

Conditions to check before valuing a reward position

A reward position only had a defensible value after the pool asset, fee component, emission status, multiplier state, and exit costs were separated. The ACX wind-down makes the emission-status check decisive because a historical reward rate cannot establish that a pool still distributes tokens.

Use this short decision checklist before comparing positions or planning a claim:

• Confirm that the specific pool shows a nonzero ACX emission rather than relying on an archived APY.
• Record pool fees in the deposited asset and token rewards in ACX as separate balances.
• Check the staked LP-token share, the multiplier, and whether a claim would reset its clock.
• Estimate Ethereum gas for every required approval, stake, claim, unstake, and withdrawal transaction.
• Review pool utilization and available withdrawal liquidity before choosing an exit size.

The checklist distinguishes an operating fee stream from a discretionary subsidy. It also exposes the failure state that mattered most: valuing ACX rewards at a displayed rate after the relevant emission parameter had changed or stopped.

Settlement kept fees separate from subsidies

Once that is set, Across settlement turned validated crosschain activity into LP fee accounting, while the Accelerating Distributor handled ACX rewards as a separate Ethereum contract path. A user's deposit entered a SpokePool, a relayer filled the destination intent, and later settlement determined repayment and rebalancing.

The dataworker groups activity into three Merkle roots covering relayer refunds, pool rebalancing, and slow fills. It proposes those roots to the HubPool on Ethereum, where UMA's Optimistic Oracle supplies the dispute mechanism. Bundles are proposed on a minimum cadence of about 1.5 hours, and the construction rules are defined through UMIP-157 and UMIP-179. ERC-7683 standardizes the intent order, but it does not merge ACX emissions into transaction fees. These layers keep operational compensation tied to transfers while governance controls the separate subsidy.

The bridge continues to operate as ACX is wound down. Across protocol rewards now require a narrower reading: utilization-based LP fees remain part of settlement, while ACX emissions belong to a legacy incentive program whose status must be read pool by pool. The durable economic signal is the fee-producing use of liquidity.

Practical questions about Across protocol rewards