For transferring 139.42 Bitcoin (BTC), a user of Bitcoin paid transaction fees totaling 83.7 Bitcoin (BTC), or $3.1 million. In the fourteen-year history of Bitcoin, the $3.1 million transaction fee is the eighth-highest.

The BTC wallet address bc1qn3d...wekrnl attempted to transfer 139.42 BTC to bc1qyf…km36t4 on November 23rd. However, the transaction fee was more than half the total amount.

Only 55.77 BTC were sent to the destination address. Antpool, the mining pool, obtained the ludicrously large mining fee on block 818087.

Social media users speculated that the sender might have chosen the expensive transaction fee, but it also seems that the sender's ignorance and the replace-by-fee (RBF) node policy were factors.

RBF enables the replacement of an unconfirmed transaction in the mempool with a new transaction that pays a higher transaction fee in order to expedite its clearing.

All Bitcoin transactions are queued up in the mempool before being approved and added to the blockchain.

Mononaut, a mempool developer, stated that it is likely that the person executing the transfer was unaware that RBF orders are non-refundable.

It's possible that the user kept changing the fees in an attempt to get it cancelled. According to the RBF history, the most recent replacement added 12.54824636 BTC in fees, a further 20% increase.

This incident is not uncommon in the crypto world. Bitcoin exchange Paxos unintentionally sent a $500,000 transaction fee for a $2,000 Bitcoin transfer in September. The F2Pool miner who confirmed the transaction in that instance gave Paxos back the $500,000 accidental transaction fee.

Nevertheless, this represents the highest Bitcoin transaction fee ever paid in US dollars, dethroning the regrettable $500,000 Paxos transfer in September. In terms of Bitcoin, the largest fee was paid in 2016 when 291 BTC in transaction fees were accidentally sent.

Sources:

https://cointelegraph.com/news/bitcoin-user-pays-3-1m-in-transition-fee-for-one-139-btc-transfer

https://mempool.space/tx/b5a2af5845a8d3796308ff9840e567b14cf6bb158ff26c999e6f9a1f5448f9aa

https://mempool.space/tx/cc455ae816e6cdafdb58d54e35d4f46d860047458eacf1c7405dc634631c570d

https://mempool.space/address/bc1qn3d7vyks0k3fx38xkxazpep8830ttmydwekrnl

https://x.com/mononautical/status/1727629348113715687