ArbitrumDAO recorded $6.19 million in income during the first half of 2026, with protocol revenue margins above 97%, according to the Arbitrum Foundation.

The more significant signal, however, came in July 2026. Robinhood Chain generated $360,000 in licensing fees for Arbitrum — approximately 35% of the DAO's income that month — in the first full month after Robinhood's Arbitrum-based Layer 2 network went live.

Under Arbitrum's Expansion Program, external chains that use its technology and settle outside of Arbitrum One and Arbitrum Nova return 10% of their net protocol revenue to the Arbitrum ecosystem. As activity on these chains grows, that arrangement could make Robinhood Chain an increasingly important revenue engine for Arbitrum. The dependency also runs in both directions: Arbitrum's income stream is now tied in part to the transaction activity of a single third-party operator, making monthly revenue more sensitive to usage swings on Robinhood Chain.

The scale of Robinhood Chain's activity is already substantial. The network processed $1.43 billion in decentralized exchange (DEX) volume over a 24-hour period in the latest data, compared with $193 million on Arbitrum One over the same timeframe.

The shift marks a notable change in Arbitrum's business model: the ecosystem is increasingly monetizing chains built on its technology through licensing arrangements, rather than relying solely on transaction fees from its flagship Arbitrum One network. The model echoes a broader trend among Ethereum Layer 2 ecosystems, where operators such as Optimism have pursued a similar strategy of licensing their stack to third-party chains — in Optimism's case, through OP Stack deployments including Coinbase's Base network.

For context, Arbitrum is one of the largest Ethereum Layer 2 scaling networks, using optimistic rollup technology to process transactions off the Ethereum mainnet while inheriting its security. Arbitrum One and Arbitrum Nova are the ecosystem's original public chains, while the Expansion Program extends the technology to third-party deployments such as Robinhood Chain.

Robinhood, a major U.S. retail trading platform, launched its Arbitrum-based Layer 2 as part of its push into on-chain crypto services. For the DAO, the figures ahead to watch are the trajectory of monthly licensing fees from Robinhood Chain and whether additional third-party chains join the Expansion Program, which would show whether this revenue source is diversifying or concentrated.