A massive, very long-ranged missile first employed by the Terran Federation during its Insurrection civil war. They are fired from a huge launcher (three times the size of a Capital Gun/Missile Launcher) and have 50% greater range than even an SBM. They have five times the explosive power of a Capital Missile and are massive - each HBM takes up as much magazine space as ten Capital Missiles.
HBM launchers require extensive hull bracing to be mounted in a starship, which limits the number that can be mounted in a hull. A battleship or superdreadnought can mount only two, a monitor four, and even a supermonitor can carry only five.