Three employees sacked by Royal & Sunalliance (RSA) for sending lewd emails were reinstated this week after disciplinary appeals.
But a further ten people had their sackings upheld.
About 80 people were suspended by RSA before Christmas after an internal investigation uncovered a series of indecent emails circulating among staff.
The decision this week means 70 of the suspended staff have kept their jobs.
The insurer would not comment on rumours that some staff would have their pay and bonuses frozen for three years.