Recent on-chain analysis caught a rare BTC transaction with an exorbitant fee. A user paid 1 BTC in fees, despite the average transaction being under $1. The payment may be an attempt to launder funds through mining.
A wallet sent out a transaction, setting up the network fee at 1 BTC, overpaying by over 100,000 times. Currently, the Bitcoin network handles transactions for under $1, so setting up the transaction to 1 BTC looks suspicious.
The transfer was flagged by Peckshield Alert, with suggestions that the sender may be engaging in miner laundering.
#PeckShieldAlert Gas Fee 1 $BTChttps://t.co/Zkj7YjwJPO pic.twitter.com/op555RSBsh
— PeckShieldAlert (@PeckShieldAlert) May 22, 2025
Miner laundering on the Bitcoin and Ethereum networks involves including transactions in a block that will send the fee to a predetermined miner. This obscures the origin of the crypto, and it is laundered as originating from miner fees.
The Bitcoin network produces $2.3M in daily fees, a much smaller inflow compared to the 450 BTC in block rewards. Some transactions carry higher fees for inclusion. In this case, the extra fee was not needed, as the chain’s mempool is not seeing any extraordinary load, despite the record BTC prices.
BTC transaction included a special message
The BTC transaction also included a special message, in the form of OP_RETURN data attached to the block. This format has been used to distribute NFTs or special inscriptions. However, even for minting special messages, a 1 BTC fee is extraordinary.
The transaction was sent out on Bitcoin Pizza Day, with the message “Payment got Gemini Pizza Block to MARA.” The rest of the message repeated “Gemini is awesome.”
The block was mined by the MARA Holdings pool, which produces around 9% of all blocks, with over 47 EH/s. Blocks with higher fees are not common, but may happen during busy network periods. Currently, the BTC network is not congested, though it remains competitive. There are fewer small-scale miners, or those that can build blocks specifically to launder funds.
The Bitcoin network is even more rarely used for messages, with Ordinals and Runes slowing to minimal activity. However, block inscriptions are always an option. In this case, the message also coincided with increased marketing activity for the Gemini exchange.
Bitcoin hashrate reaches new peak
Bitcoin mining remains a key activity, as competitors aim to produce blocks, often turning into long-term reward holders.
Miners are more professional or corporate, with most of the activity spread among the four biggest pools. Most miners did not capitulate during the latest market downturn and are still covering their costs even at near-record difficulty.
BTC hashrate expanded to over 910 EH/s, posting new records almost monthly. At current prices, all miners are in the money and are not facing stress or pressure to sell. Miners also sit on long-term reserves produced at a lower price. However, a long-term switch to transaction fees may change the nature of mining, especially after two more halvings.
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