Because profits are up a bit? (3)
I believe the answer is:
for
'because' is the definition.
(I've seen this in other clues)
'profits are up a bit?' is the wordplay.
'a bit?' says the answer is hidden in the clue (the answer is formed by a bit of the clue).
'are up' is a reversal indicator (in down clue: letters go upwards).
'rof' is hidden in the letters of 'profits'.
'rof' in reverse letter order is 'FOR'.
(Other definitions for for that I've seen before include "and 16 and 20: Notwithstanding" , "In support of" , "On behalf of" , "See 24" , "On the side of" .)