C Minor 9b5, 3rd inversion (Bb in the bass)
Also written as Cm9b5/Bb.
Notes, from the bass up
Bb (bass)DCEbGb
The same notes as C Minor 9b5 (Bb, D, C, Eb and Gb), rearranged so Bb is the lowest note. Use it to move between chords with smaller jumps across the keyboard.