Preconditions
You can view cross-chain bridge "trading volume" data on data platforms such as DeFiLlama or Dune.
You understand that one cross-chain transaction generates a separate on-chain record on both the source chain and target chain.
The double counting of cross-chain bridge trading volume is essentially a statistical caliber issue: a single fund movement leaves one record on two different chains. If data tools do not perform deduplication, the same transfer will be counted twice. This is not volume washing or data fraud, but a statistical deviation caused by the technical properties of cross-chain operations.
Step 1: Confirm the Source of Double Counting — Source Chain Record + Target Chain Record
[What to do]: Open a cross-chain transaction in a block explorer, and find its corresponding records on both chains.
[How to do it]: Locate a cross-chain bridge transaction, and check the source chain transaction hash and its matching target chain record on Etherscan.
Case A: The same funds are locked on the source chain and minted on the target chain → This is the standard workflow of cross-chain bridges: the source chain records a "lock or burn" action, while the target chain records a corresponding "mint or release" action. The two records describe the exact same economic transaction, but will be counted twice from an accounting perspective. When calculating the total trading volume of cross-chain bridges, if both records are included, a 2x deviation will be generated.
Case B: Cross-chain bridges using liquidity pool mode → Funds are deducted on the source chain and released on the target chain, with one on-chain state change on each side. The underlying logic is exactly the same as the lock-and-mint mode.
[Completion standard]: You can clearly identify the phenomenon: one single fund movement has two independent records on two different chains.
Step 2: Check the Statistical Caliber of Data Tools — "Two-sided Sum" or "Single-sided Count"
[What to do]: Confirm whether the data tool you use counts two records per transaction or only one.
[How to do it]: Check the statistical description on the cross-chain bridge dashboard of DeFiLlama or Dune.
Case A: The data tool includes both source chain and target chain records in the total trading volume → This is classified as "double counting". A typical case is the statistical deviation of Polymarket: one transaction generates two OrderFilled events, and the third-party dashboard sums both, leading to every transaction being counted twice. The total trading volume displayed on the dashboard is 2 times the actual fund flow, and cannot be directly used to judge fund direction.
Case B: The data tool only counts one end of the bridge → This is classified as "single-sided counting". Some tools have completed deduplication processing, and the displayed nominal trading volume is much closer to the actual fund flow.
[Completion standard]: You have confirmed the statistical rule of the data tool you use, i.e. whether deduplication has been performed.
High-Risk Alert
Double counting of trading volume will severely overestimate the actual fund inflow and outflow of cross-chain bridges. If you judge the fund popularity of a certain chain based on the overestimated trading volume, you may misjudge the market trend. In addition, on-chain detective ZachXBT has pointed out that the trading volume of some cross-chain bridges is also significantly inflated by hacker money laundering activities, which further interferes with data accuracy.
Common Cognitive Misconceptions
Only reading headlines of "new all-time high trading volume" without checking the calculation method of the data tool. The daily trading volume figure of a cross-chain bridge may look very large, but if records from both sides are double counted, the actual fund flow scale may only be half of the displayed number. Another common mistake is directly equating "trading volume" with "net inflow": trading volume counts the total two-sided turnover, while net inflow needs to be calculated separately as the difference between deposits and withdrawals.
Post-Operation Verification Method
Go to the cross-chain bridge section of DeFiLlama, select one bridge, and compare its "24h Volume" and "Net Inflow" data. If the gap between the two figures exceeds 2x, it means the volume statistics include both sides of the cross-chain transfer records.
Follow-up Operation Suggestions
Next time you see news that a certain cross-chain bridge hits a new trading volume high, first confirm the statistical caliber of the data. If it uses two-sided sum counting, divide the figure by 2 as a reference value for the actual fund flow. Verification channel: Compare the "Volume" column and "Net Inflow" column in the cross-chain bridge section of DeFiLlama.
