Media group Emap has snapped up internet fashion and retail information group Worth Global Style Network (WGSN) for £140m ($245m).
Emap's magazine stable already includes FHM, Heat and Empire
Emap described subscription-based WGSN.com as "the leading international online source of fashion and apparel intelligence in the retail sector".
London-based WGSN employs 172 staff and reported pre-tax profits of £4m ($7m) in 2004, on turnover of £15m.
Shares in Emap closed 0.9% lower at 806 pence on Friday.
Emap, whose magazine titles include FHM, Heat, Empire and Zoo, said it was buying WGSN from owners Marc and Julian Worth and other private shareholders.
"The acquisition of WGSN is in line with our strategy to develop and expand ... while seeking to concentrate on premium, market-leading, value-added products with a loyal customer base and superior growth profiles," said Emap chief executive Derek Carter.
WGSN was launched in 1998 to provide information on the latest trends from the catwalks and fashion trade shows, with a focus on colours, shapes, textiles, materials and brands.
Among the 15,000 firms subscribing to the service are Marks & Spencer, Next, Abercrombie & Fitch, Calvin Klein and Dolce & Gabbana.
WGSN is dependent on money from subscriptions, and annual renewal rates for the service have been in excess of 90%.
"It has the potential to be a big business and Emap is the right platform to make that happen," said seller Julian Worth.
Analysts said WGSN was a good addition to Emap's stable as traditional publishers take a leap into the online market.
"Strategically this is a good fit," said Charles Peacock, at Seymour Pierce.
"Financially it will require continued strong growth over the coming years."