Problem bank

Problem 327 of 333HardStochastic CalculusP327

Squared moves in two correlated markets

  1. Two markets move as standard Brownian motions WW and BB with correlation ρ=0.6\rho = 0.6, so dW dB=ρ dtdW\,dB = \rho\,dt.

    (a) Use the Itô product rule to find E[Wt2Bt2]E[W_t^2 B_t^2], and then Corr(W12,B12)\mathrm{Corr}(W_1^2, B_1^2).

    (b) A trend follower runs ∫01W dW\int_0^1 W\,dW in the first market and ∫01B dB\int_0^1 B\,dB in the second. Use the Itô isometry to find the correlation between the two P&Ls. Does running both books diversify more or less than the 0.6 correlation of the markets suggests?