STOCKHOLM — For as long as anyone can remember, cake has been served on Friday afternoons in the White Room, as the design department at Hennes & Mauritz is known. Designers at the Swedish fast-fashion chain take turns baking the sweets at home, finding it a convivial way to celebrate the end of the workweek.

This story first appeared in the March 25, 2008 issue of WWD. Subscribe Today.

But as enduring as that tradition has become, change has been constant in the White Room in recent years as H&M aggressively expands across Europe, the U.S. and as far abroad as China. Twenty years ago, for instance, there were only eight designers in the department. The majority of their time was devoted to buying ready-made garments from overseas suppliers. There were no trend boards, no computers and no library packed with books ready to be consulted for inspiration.

Today, there are more than 100 designers in the bustling department. Twenty designers alone deal with prints. Most of the staff are Swedes, many of whom have worked for years at H&M. But there are also designers from countries such as England, Holland, Switzerland, Belgium, Denmark, Norway, Finland, Australia, Argentina, the U.S., South Africa and Portugal. No one counts how many designs are produced a year, but it’s safe to estimate there are thousands, ranging from drainpipe jeans for teenage girls to maternity dresses for expectant mothers.

Margareta van den Bosch, who has overseen the White Room since 1988, when Hennes & Mauritz was still a regional Scandinavian chain just tapping into its worldwide ambitions, engineered most of the transformation.

She helped H&M refine the notion of cheap chic, for which it has become famous, with an acute nose for trends and a keen understanding of the fashion-hungry consumers the chain wanted to court; scoured flea markets like any good designer of her generation; gave H&M a fashion vocabulary that took it beyond cheap basics, and hit on the very successful idea of collaborating with designers like Karl Lagerfeld and Roberto Cavalli on one-off collections at cheap prices.

But as van den Bosch, now 65, scales back her duties (earlier this year she said she would move into semiretirement and pass the design directorship to one of her protégés, Ann-Sofie Johansson), H&M is getting ready for a new era.

Last year, the company launched an upscale fashion chain called COS, and earlier this month H&M purchased a 60 percent stake in privately owned Fabric Scandinavian AB, makers of the trendy Cheap Monday fashion label. Both developments show the retailer is rapidly moving toward a multibrand strategy.

The firm, which operates more than 1,500 stores in 28 countries, is also developing a home line, which should see the light of day next year. In 2007, H&M’s profit climbed 21 percent to 19.17 billion kronor, or $2.83 billion at average exchange, on sales of 78.35 billion kronor, or $11.57 billion, up 15 percent.

But even as all the change whirls, Johansson and van den Bosch both emphasize the notion of continuity and the importance of H&M keeping its thumb on the pulse of the trends.

“I want to continue Margareta’s good work,” said Johansson, 44. “My goal is to continue to develop it and to improve things. We can always be better at what we do. I think we can always be more exciting and inviting for customers.”

Johansson, dressed in a beige COS cardigan and pink T-shirt, and van den Bosch, peering over black spectacles and wearing a vintage MaxMara green sweater, may be of different generations, but it’s clear they share similar views about the future development of H&M’s fast-paced fashion culture.

Van den Bosch hired Johansson in 1990 as a design assistant after the latter spent three years working as a sales clerk in an H&M store. Johansson worked herself up through the ranks, gaining experience in various domains. In 1994 she became a designer for the Divided Black collection, before becoming a designer in the ladies’ department in 2005.

“We both love fashion,” said van den Bosch. “That’s what we have in common.”

The change in command will be gradual. The first collections under Johansson’s purview will launch next year. Van den Bosch plans to remain a significant presence at H&M. On the day of the interview, for example, she spent the better part of the morning ushering financial analysts around an H&M store here.

“I don’t want to work as much as I did,” said van den Bosch. “Now, I’ll be the creative adviser. But I can’t work as much as I have since I want to have time for other things in my life.”

“I’m going to ask Margareta for her advice and opinion, which is very reassuring,” said Johansson.

One project van den Bosch won’t abdicate is H&M’s myriad designer collaborations. They have proved wildly successful both commercially and in terms of marketing and helped to elevate the retailer’s image among trendier clients.

“It exceeded my expectations,” the soft-spoken van den Bosch said of the tie-ups, which started with Karl Lagerfeld and went on to include Stella McCartney and Viktor & Rolf. “We proved that fashion isn’t only a question of price.”

Van den Bosch said she already was working on the next designer collaboration, to be unveiled this fall, but declined to reveal details. “It will be something completely unexpected,” she said.

Last year H&M offered collections designed by Cavalli and Madonna. This spring, the company is changing gears by collaborating with a textile firm, Marimekko of Finland, renowned in the Seventies for its bold prints.

The design philosophy at H&M is referred to as a pyramid, with ultrafashionable looks at the point on top and basic items filling in the bottom. In the middle are more moderate looks. In other words, while fashionable styles may drive customers into stores, it’s the basics that sell and thus account for volume.

A trend group of 10 designers meet on a regular basis to discuss the direction collections will take. Subjects range from pop culture to museum exhibits. Street trends are examined. (H&M designers are dispatched to different cities around the world on inspiration trips on a regular basis.)

“Paris and London are good places to see what’s happening,” said Johansson. “I also like New York and Tokyo for trendspotting.”

Inspiration boards are created, books are consulted, designers tap into a plush collection of vintage clothes — there are racks of confections (most purchased by van den Bosch) — and the designing begins.

H&M is famous for the speed it feeds new collections into stores. As little as two weeks are required to get an item from the drawing board to the shop floor.

The process starts when new designs are entered into computers and the data are zapped to factories around the world, including Asia and Europe. Only the most complicated samples are stitched up in the small atelier H&M operates onsite. Otherwise, samples arrive back in Stockholm as little as a week after initial designs are sent to the factory. Modifications, if needed, are made equally fast.

Despite its ability to react quickly, van den Bosch downplays H&M’s speed as “really not so important. It’s more important to understand the long-term trends. Silhouettes don’t change so fast. Skinny jeans and narrow trousers — people still like it. Dresses are popular and they hadn’t been in for a long time. It takes a long time for silhouettes to change.”

In the past, betting too heavily on edgier fashion looks has burned H&M. This occurred in 2001, for example, when the chain introduced too much color as fashion got bolder. “People weren’t used to it,” said van den Bosch. “We had a bad season.”

Now, van den Bosch said, the company is more conservative with bold new fashion, which she said “can be scary.”

“You have to choose the trends,” said Johansson. “You can’t do everything. It has to be good for our customers. You can analyze the selling figures from previous seasons and know what’s right for our customers.”

So-called trend collections are used to test out new directions. “We try it out in small volumes,” said Johansson.

That’s where H&M’s nimble production and distribution are an advantage. If the trend takes off, the company can bulk up with lightning efficiency. “Lead times have been reduced dramatically over the last 10 years thanks to IT [information technology],” explained Nils Vinge, head of investor relations at H&M. “There is novelty in the store on a daily basis.”

Fast-fashion firms have often been accused of copying runway trends, sometimes getting the latest styles into their stores before the designer collections are available at retail. Though van den Bosch admitted to being inspired by designers — particularly Prada and Marni — she bristled at the suggestion that H&M tries to rip off the runway.

“Most of our collections are made before the catwalk season starts,” she said.

Anyway, van den Bosch said, catwalks aren’t as important as before in dictating the trends. “Celebrities set the trends now,” she said. “That and what’s going on the street.”

“Kate Moss is still another influence,” said Johansson. “Rihanna is another, as is Chloë Sevigny and models like Agyness Deyn. Our costumers aren’t interested in [catwalk] designers. They look at celebrities.”

Van den Bosch agreed that that is one of the biggest changes in the industry since she started. “There has been a big change in the market in that people mix high and low [brand fashion],” she said. “When I started at H&M, a fashion journalist would have a total look. You would be ashamed to dress like that today.”