Bitcoin’s network recorded a rare two-block chain reorganization on March 24, 2026, after competing mining pools Foundry USA and AntPool discovered conflicting blocks just 12 seconds apart. The heavier chain prevailed within minutes, no confirmed user transactions were reversed, and the network continued operating normally.
TLDR Keypoints
- What happened: A two-block reorganization occurred when AntPool and Foundry USA found competing blocks at nearly the same time, forcing the network to discard the shorter chain and adopt the longer one.
- Who was involved: Foundry USA, AntPool, and ViaBTC were the mining pools at the center of the event, with Foundry ultimately mining seven consecutive blocks to cement its chain as canonical.
- Outcome: The network resolved the split without disruption; orphaned transactions returned to the mempool and were re-confirmed in subsequent blocks.
Foundry and AntPool Found Competing Blocks 12 Seconds Apart
The reorg occurred at block height 941,880 through 941,882. AntPool found block 941,881 at 15:49:35 UTC, while Foundry USA discovered a competing block at the same height just 12 seconds later, at 15:49:47 UTC, according to CoinDesk.
Bitcoin’s latest reorg unwound two confirmed blocks simultaneously, a rare occurrence on a network where single-block reorgs are already uncommon. The chain resolved without lasting disruption.
With both pools broadcasting valid blocks to different parts of the network, a temporary chain split formed. ViaBTC extended the AntPool side, but Foundry USA subsequently mined blocks 941,883 through 941,886, producing seven consecutive blocks that made its chain the heaviest by cumulative proof of work.
The AntPool and ViaBTC blocks were orphaned. The losing pools forfeited the block subsidy of 3.125 BTC per block plus transaction fees. Transactions contained in those orphaned blocks returned to the mempool and were picked up by subsequent blocks on the winning chain.
Bitcoin researcher b10c was the first to publicly flag the event, describing it as “a rare-ish two block fork/reorg between Foundry and AntPool+ViaBTC.”
Why a Two-Block Reorg Is Notable but Not Alarming
A chain reorganization occurs when two miners find valid blocks at nearly the same time, creating competing versions of the blockchain. The network temporarily splits, with different nodes following different chain tips, until one side accumulates more proof of work and becomes the canonical chain.
Single-block orphans happen roughly once every few weeks due to normal network propagation latency. A two-block reorg is rarer because it requires a second consecutive block to extend the losing chain before the network converges, a sequence that demands specific timing and propagation conditions.
No deep reorg has successfully threatened Bitcoin’s mainnet in over a decade. The event on March 24 resolved deterministically through Bitcoin’s heaviest-chain rule once block propagation completed across the network. For context, Bitcoin’s price trajectory and broader market dynamics remain a far larger concern for most holders than a brief chain split.
Industry-standard practice requires 6 block confirmations before a Bitcoin transaction is considered final for custody purposes, well above the 2-block reorg depth, explaining why the incident had negligible impact on end users.
Exchanges and custodians typically require six confirmations before crediting Bitcoin deposits. A two-block reorg falls well short of that threshold, which is precisely why the standard exists. No confirmed user transactions were reversed.
Hashrate Concentration Makes Near-Simultaneous Finds More Likely
The reorg comes against a backdrop of increasing mining pool concentration. Network hashrate has retreated to approximately 920 EH/s, down from a record near 1 zetahash reached in 2025. With Bitcoin trading at roughly $70,075, well below the estimated $88,000 average production cost, smaller miners have been exiting the network or consolidating under larger pool operators.
Mining difficulty dropped 7.76% the preceding Saturday, the second-largest negative difficulty adjustment of 2026. That decline reflects the ongoing miner exodus driven by the cost-price squeeze.
When fewer, larger pools control a greater share of hashrate, the probability of near-simultaneous block discoveries increases. Two dominant pools operating at high hash rates are more likely to find valid blocks within seconds of each other than a more distributed set of smaller miners would be.
This structural shift does not represent a security threat to Bitcoin. The network’s consensus mechanism handled the competing chains exactly as designed. But it does mean that short reorgs of this kind may become slightly more frequent as long as mining infrastructure remains concentrated among a handful of major pools.
What to Watch Going Forward
Neither Foundry USA, AntPool, nor ViaBTC had issued public statements acknowledging the event at the time of writing. Whether any of the involved pools were using optimized block relay protocols like FIBRE or Compact Blocks, which reduce propagation latency, remains unclear.
Readers tracking Bitcoin network health can monitor future reorg events through tools like Forkmonitor.info, which logs chain splits and orphaned blocks in real time. The site provides alerts when forks are detected and tracks which pools are involved.
The Fear and Greed Index sits at 11, deep in “Extreme Fear” territory, reflecting broader market anxiety unrelated to the reorg itself. With Bitcoin trading roughly $18,000 below estimated miner breakeven costs, the hashrate decline and pool consolidation that contributed to this event are likely to persist until price conditions improve or less efficient miners fully exit the network.
Disclaimer: This article is for informational purposes only and does not constitute financial or investment advice. Cryptocurrency and digital asset markets carry significant risk. Always do your own research before making decisions.