  We examine the behaviour of circular geodesics describing orbits of neutral
test particles around an extreme Kerr-Newman black hole. It is well known that
the radial Boyer-Lindquist coordinates of the prograde photon orbit $r=r_{\rm
ph}$, marginally bound orbit $r=r_{\rm mb}$ and innermost stable orbit
$r=r_{\rm ms}$ of the extreme Kerr black hole all coincide with the event
horizon's value $r=r_+$. We find that for the extreme Kerr-Newman black hole
with mass $M$, angular momentum $J$ and electric charge
$Q=\pm\sqrt{M^2-J^2/M^2}$ ($|J|\le M^2$) the coordinate equalities $r_{\rm
ph}=r_+$, $r_{\rm mb}=r_+$ and $r_{\rm ms}=r_+$ hold if and only if $|J|$ is
greater than or equal to $M^2/2$, $M^2/\sqrt{3}$ and $M^2/\sqrt{2}$,
respectively.
