Best Buy, the US electricals giant that snapped up half of Carphone Warehouse’s retail business last month for £1.1 billion, has announced a drop in first-quarter earnings.

The US retailer said earnings were US$179 million (£91.7 million) in the quarter to May 31, down from US$192 million (£98.3 million) in the same period the year before. Like-for-likes were up 3.7 per cent.

Best Buy, which at the end of the quarter operated Best Buy Mobile shops in 599 of its 957 eponymous stores as part of an earlier joint venture with Carphone Warehouse, said the division had shown strong double-digit gains. It will install Best Buy Mobile areas in all stores by the end of the year.

As a result, Best Buy will roll out the Best Buy Mobile relationship with Carphone Warehouse to its stores in Canada, China, Mexico and Turkey. Carphone Warehouse chief executive Charles Dunstone will head the international expansion of Best Buy Mobile, it added.

As part of last month’s deal, Best Buy will launch eponymous standalone stores in the UK in 2009.

Best Buy increased its domestic market share by 1.5 percentage points year on year in the quarter, driven by growth in TVs, computing, gaming and mobile phones.

Revenues rose 13 per cent to US$9 billion (£4.61 billion). Online sales climbed 30 per cent for the quarter as Best Buy introduced initiatives such as improved navigation, online customer reviews and ratings.

Domestic sales were up 11 per cent or 3.5 per cent on a like-for-like basis and international revenue increased by 26 per cent, or a like-for-like gain of 4.7 per cent.