Watches of Switzerland warned of a “potentially more challenging trading environment” for the rest of the year despite reporting strong growth in the past three months.

Group sales jumped 31% year on year to GBP 391 million ($460.2 million) in the first fiscal quarter, which ended July 31, the UK-based company reported last week. Revenue in the UK and Europe rose 8% to GBP 239 million ($281.4 million), while US sales doubled to GBP 152 million ($179 million) as the company acquired several businesses, including jewelry chain Betteridge.

The world’s largest retailer of Rolex timepieces maintained its fiscal-year sales forecast of GBP 1.45 billion to GBP 1.5 billion ($1.71 billion to $1.77 billion) in spite of concerns about a slowdown in the remaining three quarters. The fiscal year runs through April 2023.