Why Did Bitmain’s Antpool ‘Stop Mining’ SegWit Blocks?

Antpool, the Bitcoin mining pool owned by hardware manufacturer Bitmain, has stopped mining Segregated Witness (‘SegWit’) blocks.

A Question Of ‘Charity’?

In a move which has sparked suspicion among cryptocurrency figures, data from the past seven days of block mining shows Bitmain mining blocks of under 1 megabyte – smaller than SegWit blocks mined by other pools.

“AntPool no longer includes SegWit txs in Bitcoin (BTC) blocks,” one Twitter account confirmed October 30.

If there are enough non-SW transactions to fill up Core’s 1MB base blocks and they pay higher fees than the SW transactions, why should (it) be charitable?

The curious statistics contrast with Bitmain’s desire to increase the Bitcoin block size limit as an alternative to the off-chain scaling options favored by SegWit proponents.

The apparent conflict was not lost on the industry, the research team of Hong Kong-based trading platform BitMEX also highlighting the sub-megabyte blocks on Twitter.

“Despite Bitmain’s strong support for larger blocks, Antpool has recently been producing smaller blocks (below 1MB), while other pools produce larger blocks,” staff commented.

Despite Bitmain's strong support for larger blocks, Antpool has recently been producing smaller blocks (below 1MB), while other pools produce larger blocks.

Is Antpool/Bitmain excluding SegWit format transactions?https://t.co/rDQIlCearW pic.twitter.com/5cJgn0iLxd

— BitMEX Research (@BitMEXResearch) October 29, 2018

Worst Of Both Worlds

Reactions to BitMEX included claims Bitmain, through excluding SegWit, could continue to use the highly-controversial Covert ASICBoost mining technique it had previously claimed was “not practical.”

Last month, the company began rolling out Overt ASICBoost for its Antminer hardware family, a move which similarly drew suspicion from commentators.

In a further nuance meanwhile, Blockstream’s Warren Togami noted that despite non-SegWit blocks ostensibly having a higher fee attached, the blocks Antpool had chosen to mine in fact contained less in fees than the SegWit blocks it was avoiding.

Bitmain continues to hold a monopoly on Bitcoin mining through control of Antpool and BTC.com, the latter regularly mining the most blocks on a given day.

The proportion of transactions using SegWit had continued to climb in recent months, reaching an all-time high of 48 percent in early October before dropping.

What do you think about Antpool’s mining behavior? Let us know in the comments below!

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