Bb Major 9#11, 5th inversion (E in the bass)
Also written as Bbmaj9#11/E.
Notes, from the bass up
E (bass)A#DE#AB#
The same notes as Bb Major 9#11 (E, A#, D, E#, A and B#), rearranged so E is the lowest note. Use it to move between chords with smaller jumps across the keyboard.