B Minor Major 9th, 4th inversion (C# in the bass)
Also written as Bm(maj9)/C#.
Notes, from the bass up
C# (bass)BDF#A#
The same notes as B Minor Major 9th (C#, B, D, F# and A#), rearranged so C# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.