B¯→K*γfromD→K*l¯ν

The $\overline{B}\to K^{*}\gamma$ branching fraction is predicted using heavy quark spin symmetry at large recoil to relate the tensor and (axial-)vector form factors, using heavy quark flavor symmetry to relate the B decay form factors to the measured $\overrightarrow{D}{K}^{*}\overline{l}\nu$ form factors, and extrapolating the semileptonic B decay form factors to large recoil assuming nearest pole dominance. This prediction agrees with data surprisingly well, and we comment on its implications for the extraction of $|V_{\mathrm{ub}}|$ from $\overline{B}\to \rho l\overline{\nu }.$