  The extremely large magnetoresistance (XMR) observed in many topologically
nontrivial and trivial semimetals has attracted much attention in relation to
its underlying physical mechanism. In this paper, by combining the band
structure and Fermi surface (FS) calculations with the Hall resistivity and de
Haas-Van Alphen (dHvA) oscillation measurements, we studied the anisotropy of
magnetoresistance (MR) of ReO$_3$ with a simple cubic structure, an "ordinary"
nonmagnetic metal considered previously. We found that ReO$_3$ exhibits almost
all the characteristics of XMR semimetals: the nearly quadratic field
dependence of MR, a field-induced upturn in resistivity followed by a plateau
at low temperatures, high mobilities of charge carriers. It was found that for
magnetic field \emph{H} applied along the \emph{c} axis, the MR exhibits an
unsaturated \emph{H}$^{1.75}$ dependence, which was argued to arise from the
complete carrier compensation supported by the Hall resistivity measurements.
For \emph{H} applied along the direction of 15$^\circ$ relative to the \emph{c}
axis, an unsaturated \emph{H}$^{1.90}$ dependence of MR up to
9.43~$\times$~$10^3$$\%$ at 10~K and 9~T was observed, which was explained by
the existence of electron open orbits extending along the $k_{x}$ direction.
Two mechanisms responsible for XMR observed usually in the semimetals occur
also in the simple metal ReO$_3$ due to its peculiar FS (two closed electron
pockets and one open electron pocket), once again indicating that the details
of FS topology are a key factor for the observed XMR in materials.
