Ethereum Bridges: 4 Months On

Harith Kamarul
Etherscan Blog
Published in
4 min readOct 6, 2021

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In June, we took a look at activity around bridges on Ethereum. Key highlights included the dominance of Polygon and USDC as well as the peaking of growth in May. A lot has happened since then. Four months on, we revisit the same metrics and see how far they have shifted:

  • Balance held by the respective chains
  • Deposits and withdrawals on each chain
  • Breakdown of bridged tokens

The number of bridge addresses we track on our Bridges dashboard is now 62 (up from 36 in June), connecting Ethereum with 19 other Layer 1 chains and 16 of its own Layer 2 chains.

Browse through a list of these bridges on Blockscan.

Total balance held across all chains tracked in June amounted to $8 billion. Today, that number exceeds $18 billion.

Any guesses how this TVL stacks up against DeFi platforms? Scroll to the bottom to find out!

Balance Held

Compared to the all-purple seen previously, the balances held across bridges are better distributed this time around. Polygon’s share dropped from ~90% to ~30%. Axie Infinity’s move to their Ronin sidechain has proven a major success, the explosion in activity and AXS token value garnering them 25% of bridge locked value. Avalanche and Arbitrum round out the top four.

Top four chains make up half of bridge TVL.

While Polygon’s total balance dropped from ~$7 billion to ~$5.5 billion, other bridges made huge progress in adding value. Only two non-Polygon bridges had balances surpassing $100 million in June; today three bridges hold more than $1 billion each and 15 have exceeded the $100 million mark.

Full table here.

Interestingly, while Optimistic Rollup chains have launched and accumulated deposits, Layer 2’s share of total TVL only eked out an additional 3% from June.

‘Both’ refers to bridges that lock value for multiple chains across Layer 1 and Layer 2.

Zooming into these Layer 2 chains, Optimistic Rollups make up close to two thirds of the $2.8 billion total share. The bulk of this total are in Arbitrum (~$1.5 billion) and dYdX (~$700 million).

Categorization based on the amazing L2BEAT website.

Deposits & Withdrawals

Deposits actually slowed down following the May peak, with Polygon deposits dropping being a primary factor. September roared back, as deposits totaling $12 billion came in led by Arbitrum, Avalanche, Ronin, Solana and dYdX.

Play around with the deposits chart here.

Withdrawals retained its May levels for the next three months, leading to limited change in net inflow through August. In September, withdrawals increased but paled in comparison to the increase in deposits.

Do a side-by-side comparison of deposits and withdrawals in the same dashboard.

Bridged Tokens

As the main token deposited into Axie Infinity’s Ronin, AXS shot to the top of the list. Ether dropped to second place, partially explained by WETH appearing at #4 as several new bridges accepted it instead of Ether. Total AAVE amounts dropped, an interesting finding given that it was widely used in Polygon and is a major partner for the Avalanche Rush. Users may have been waiting for the launch to deposit into Avalanche.

Tokens related to Polygon (MATIC, QUICK, AAVE) dropped down the pecking order as users delved into other chains. Other than the usual suspects of stablecoins and WBTC, FTM also gained a noticeable share of the pie.

AXS is by far the most concentrated token per bridged chain out of the top tokens, with AXS locked in Ronin making up 56% of its circulating supply!

Ronin bridge AXS amounts taken from token holder chart, circulating supply from CoinGecko.

The combined $18 billion locked in Ethereum bridges exceed TVL for every single DeFi app across all chains, jumping from #8 four months ago.

Credit for DeFi rankings to Defi Llama.

The burgeoning growth of chains and interconnecting bridges them will continue to be a massive part of Web3. The Explorer-as-a-Service product, Blockscan list of bridges and Etherscan Bridges dashboard are some of our attempts to support this growth.

What are other ways we can help? Let us know in the replies!

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