Bb 13sus4, 3rd inversion (G# in the bass)
Also written as Bb13sus4/G#.
Notes, from the bass up
G# (bass)B#GA#D#E#
The same notes as Bb 13sus4 (G#, B#, G, A#, D# and E#), rearranged so G# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.