  We present thermodynamic material and transport properties for the extreme
conditions prevalent in the interiors of massive giant planets and brown
dwarfs. They are obtained from extensive \textit{ab initio} simulations of
hydrogen-helium mixtures along the isentropes of three representative objects.
In particular, we determine the heat capacities, the thermal expansion
coefficient, the isothermal compressibility, and the sound velocity. Important
transport properties such as the electrical and thermal conductivity, opacity,
and shear viscosity are also calculated. Further results for associated
quantities including magnetic and thermal diffusivity, kinematic shear
viscosity, as well as the static Love number $k_2$ and the equidistance are
presented. In comparison to Jupiter-mass planets, the behavior inside massive
giant planets and brown dwarfs is stronger dominated by degenerate matter. We
discuss the implications on possible dynamics and magnetic fields of those
massive objects. The consistent data set compiled here may serve as starting
point to obtain material and transport properties for other substellar H-He
objects with masses above one Jovian mass and finally may be used as input for
dynamo simulations.
