Jan 12 - SuperGroup, the British company behind the Superdry fashion brand, forecast year profit at the upper end of expectations after posting a 90 percent increase in sales over the key Christmas period.

Superdry

SuperGroup, whose clothes are a favourite of celebrities such as David Beckham, Leonardo DiCaprio and Zac Efron, said on Wednesday it made sales of 65.1 million pounds ($101.5 million) in the nine weeks to Jan. 2.

It said retail sales of its trademark T-shirts, hoodies, check shirts and jogging bottoms surged 93.6 percent to 51.7 million pounds, while wholesale sales increased 77.8 percent to 13.4 million pounds.

SuperGroup was one of 2010's most successful IPOs, listing at 500 pence in March and hitting a high of 1,660 pence on Dec. 13.

But its shares fell sharply after a Dec. 15 update cautioned that raw material prices may affect gross margins in the 2011-12 year.

It said on Wednesday that as a result of renegotiations with its suppliers and selected price increases it had largely mitigated the rise in cotton prices, forecasting no impact to 2011 gross margins and a hit of no more than 200 basis points in 2012.

The stock closed at 1,185 pence on Tuesday, valuing the business at 937 million pounds.

(Reporting by James Davey; Editing by Julie Crust)