Bb 7b13, 1st inversion (D in the bass)
Also written as Bb7b13/D.
Notes, from the bass up
D (bass)E#G#F#A#
The same notes as Bb 7b13 (D, E#, G#, F# and A#), rearranged so D is the lowest note. Use it to move between chords with smaller jumps across the keyboard.