The US division increased market share and boosted the Kay chain to the top spot in the speciality retail jewellery sector.
The retailer's UK brands, Earnest Jones and H Samuel also experienced growth that outperformed the total retail market. Like-for-like sales for the division grew by 3 per cent. Operating profit reached£78.2 million, an increase of 2.1 per cent on the previous year.
In the year to date, the retailer experienced low single-digit like-for-like sales growth, after taking into account the change in the timing of Easter, which caused the UK division to show a small decrease in like-for-like sales.
The retailer has focused on diamond sales that it said requires a high level of customer service.
Group chairman James McAdam CBE said: These results reflect our successful implementation of the group's strategies on both sides of the Atlantic. However the full extent of the group's progress has not been reflected in the reported results because of further weakening of the average US Dollar exchange rate.'