Bayesian portfolio construction combining a prior of equilibrium (market-implied) expected returns boldsymbolPi — obtained by reverse-optimisation boldsymbolPi = γ,boldsymbolΣ,boldsymbolw_mkt — with investor views boldsymbolPboldsymbolμ = boldsymbolQ + boldsymbolvarepsilon to produce a posterior boldsymbolμ_BL = [(τboldsymbolΣ)^-1 + boldsymbolP^TboldsymbolΩ^-1boldsymbolP]^-1,[(τboldsymbolΣ)^-1boldsymbolPi + boldsymbolP^TboldsymbolΩ^-1boldsymbolQ]. Solves Markowitz's notorious corner-solution / input-sensitivity problem by anchoring to equilibrium and only tilting where the investor has high conviction.