A Major 9#11, 4th inversion (B in the bass)
Also written as Amaj9#11/B.
Notes, from the bass up
B (bass)D#AC#EG#
The same notes as A Major 9#11 (B, D#, A, C#, E and G#), rearranged so B is the lowest note. Use it to move between chords with smaller jumps across the keyboard.