Employee take-up rates for Britannia Building Society's flexible benefits scheme that was launched in May have reached a figure of 17%.
Buying holiday was the most popular option with 5.9% of employees using their flex allowance to buy extra days.
Andrea Adams, change manager for group reward, said: "We were hoping for a take-up rate of around 20% but we think that was perhaps a bit high."
One reason for the lower rate was that the holiday year for all staff was changed to start in May to coincide with the flex launch.
Staff with holiday to use before May were allowed to sell spare days. Although 292 employees chose to do so, this was not incorporated into the total take-up rate calculated for those electing to sell holiday through flex.
