  Hypervelocity stars (HVS) move so fast that they are unbound to the Galaxy.
When they were first discovered in 2005, dynamical ejection from the
supermassive black hole (SMBH) in the Galactic Centre (GC) was suggested as
their origin. The two dozen HVSs known today are young massive B stars, mostly
of 3-4 solar masses. Recently, 20 HVS candidates of low mass were discovered in
the Segue G and K dwarf sample, but none of them originates from the GC. We
embarked on a kinematic analysis of the Segue HVS candidate sample using the
full 6D phase space information based on new proper motion measurements. Their
orbital properties can then be derived by tracing back their trajectories in
different mass models of our Galaxy. We present the results for 14 candidate
HVSs, for which proper motion measurements were possible. Significantly lower
proper motions than found in the previous study were derived. Considering three
different Galactic mass models we find that all stars are bound to the Galaxy.
We confirm that the stars do not originate from the GC. The distribution of
their proper motions and radial velocities is consistent with predictions for
runaway stars ejected from the Galactic disk by the binary supernova mechanism.
However, their kinematics are also consistent with old disk membership.
Moreover, most stars have rather low metallicities and strong $\alpha$-element
enrichment as typical for thick disk and halo stars, whereas the metallicity of
the three most metal-rich stars could possibly indicate that they are runaway
stars from the thin disk. One star shows halo kinematics.
