  First-principles band structure investigations of the electronic, optical and
magnetic properties of Mo-doped In$_2$O$_3$ reveal the vital role of magnetic
interactions in determining both the electrical conductivity and the
Burstein-Moss shift which governs optical absorption. We demonstrate the
advantages of the transition metal doping which results in smaller effective
mass, larger fundamental band gap and better overall optical transmission in
the visible -- as compared to commercial Sn-doped In$_2$O$_3$. Similar behavior
is expected upon doping with other transition metals opening up an avenue for
the family of efficient transparent conductors mediated by magnetic
interactions.
