Bitcoin block reorg not selfish mining: researcher debunks attack
A rare Bitcoin block reorganization at height 941880 sparked claims of a malicious “selfish-mining” attack. The episode briefly split the chain into two equal-length histories, with AntPool mining blocks 941881–941882 and ViaBTC producing competing blocks on the same heights. Foundry USA also mined its own versions of those blocks.
In the tie-break, Foundry USA continued mining blocks 941883–941885, orphaning the AntPool and ViaBTC branches. The researcher says the behavior matches expected network conditions rather than coordinated selfish-mining.
Key points cited: (1) incentives look wrong for selfish mining, because the reorg occurred during a low-fee period and only netted Foundry about 0.025 BTC in transaction fees; (2) on-chain data reportedly shows Foundry mined again on top of the AntPool/ViaBTC blocks before switching back to its chain—something a withholding/hidden private chain would not do.
The explanation offered is standard Bitcoin network latency plus the use of specific Bitcoin Core commands. Overall, the “selfish mining” narrative is rejected based on the observed on-chain actions and poor economic fit for an attacker.
Neutral
This news is likely neutral for trading. It addresses community fear about a Bitcoin block reorg being a “selfish-mining” attack, but the researcher’s argument is based on observed chain behavior and weak attacker incentives (only ~0.025 BTC in fees during a low-fee period, plus behavior inconsistent with withholding a private chain).
In the short term, such clarifications can reduce volatility driven by rumor—similar to prior incidents where suspected protocol-level anomalies were later explained by reorg mechanics, node latency, or client configuration. Traders may see less need for defensive positioning solely on the basis of reorg headlines.
In the long term, the event is a reminder that reorgs can occur without indicating market manipulation. However, since it doesn’t reveal a security breach or sustained profitability attack, it’s unlikely to change broader network risk perceptions materially. Net effect: minimal impact on price direction, with sentiment relief more likely than fundamentals-driven moves.