In 2013 researchers showed that #Bitcoin miners with far less than 51% of the hashrate can profit by secretly withholding blocks.

In 2013 researchers showed that #Bitcoin miners with far less than 51% of the hashrate can profit by secretly withholding blocks. What threshold did they find, has it ever been seen in the wild, and why does it challenge the “honest majority” assumption?

Eyal and Sirer (2013) showed selfish mining is profitable above α > (1-γ)/(3-2γ). This is 33% when γ=0 (no propagation edge) and 25% at γ=0.5. Current protocol can push the threshold near zero. No confirmed intentional cases on Bitcoin mainnet (possible accidental latency effects in 2015; anomalies noted on smaller chains). It challenges the honest-majority assumption because a minority can earn more than its fair share, drawing rational miners and risking progressive centralization.