Bitcoin Transfer Estimates Can Vary Sixfold Depending on Measurement Method

A new working paper from the Bank for International Settlements (BIS) reveals that estimates of Bitcoin's onchain transfer value can vary by up to sixfold depending on the measurement method used.

The BIS researchers, Timothy Aerts, Ronald Heijmans, Jan Paulick and Violeta Vuletic, examined different methods for estimating onchain transfer values in their paper, BIS Working Paper No. 1377, published in September 2026.

The issue stems from Bitcoin's transaction structure, which uses a system of unspent transaction outputs (UTXOs), rather than account balances. When a user spends Bitcoin, the entire UTXO being used must be spent in the transaction. If the user spends less than the value of that UTXO, the remaining funds are typically sent back to the user as 'change'.

Researchers must rely on heuristics to identify change, and these assumptions can dramatically alter reported transfer volumes.