Supermarkets are showing strong year-on-year performance in magazine retailing, according to the latest edition of Comag's Insight publication. The distributor singles out Sainsbury, which sold £2.4m of news and magazines in the first week in October ­ some £425,000 more than in the same week last year. However, it points out that Sainsbury's market share has declined from 16.1% for the same period last year to 15.8%. Meanwhile, news and magazines sales through Tesco ­ which increased its market share to 22.5% of the UK grocery market against 21% in the same period last year ­ produced £3.86m in the first week of October, up 4.3% on the previous week. Magazines alone produced £2.59m ­ an increase of 5.7%. Tesco says that the top 110 titles through its stores account for 75% of sales, and a six-month merchandising trial to look after all aspects of display/availability of these titles will start on October 15. Comag's Insight also reveals that WH Smith is aiming to open 50 branded Christmas stores that will carry a range of 150 magazines for a 12-week period. Costcutter has joined with WHSmith News to launch its own promotional group. Some 250 of Costcutter's 650 stores that sell news and magazines stores will take part. {{CTN }}