We use new Gaia measurements to explore the origin of the highest velocity stars in the hypervelocity star (HVS) survey. The measurements reveal a clear pattern in B-type stars. Halo stars dominate the sample at speeds of ≃100 km s‑1 below Galactic escape velocity. Disk runaway stars have speeds up to ≃100 km s‑1 above Galactic escape velocity, but most disk runaways are bound. Stars with speeds ≳100 km s‑1 above Galactic escape velocity originate from the Galactic center. Two bound stars may also originate from the Galactic center. Future Gaia measurements will enable a large, clean sample of Galactic center ejections for measuring the massive black hole ejection rate of HVSs, and for constraining the mass distribution of the Milky Way dark matter halo.
