Alpha Airports has admitted that it has lost up to £2.5m as part of a European-wide fraud.
After announcing in January that it was investigating a scam, the in-flight caterer said it had now issued legal proceedings against a UK-based third-party supplier.
It refused to release further details but said it expected the case to be completed within three to six months.
Despite the investigation, annual turnover at the group was up by 12.9% to £550.9m.
Pre-tax profit grew by 40.4% from £13.1m last year to £18.4m.
Chairman Graham Frost said the result was thanks to "a much stronger performance in the second half of the year".
"In a highly competitive environment, and after the disappointing first half result, this is an acceptable performance," he added.
In the UK, operating profit was down 33% to £8.8m despite a 9% jump in turnover.
Outside the UK, the company saw a 98% increase in operating profit from £6.3m to £12.5m.
By Tom Bill
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