  The young nearby solar-type star HD 91962 is a rare quadruple system where
three companions revolve around the main component with periods of 170.3 days,
8.85 years, and 205 years. The two outer orbits are nearly co-planar, and all
orbits have small eccentricities. We refine the visual orbit of the outer pair,
determine the combined spectro-interferometric orbit of the middle 8.8-yr pair
and the spectroscopic orbit of the inner binary. The middle and inner orbits
are likely locked in a 1:19 resonance, the ratio of the outer and middle
periods is ~23. The masses of all components are estimated (inside-out: 1.14,
0.32, 0.64, 0.64 solar mass), the dynamical parallax is 27.4+-0.6 mas. We
speculate that this multiple system originated from collapse of an isolated
core and that the companions migrated in a dissipative disk. Other multiple
systems with similar features (coplanarity, small eccentricity, and period
ratio around 20) are known.
