IN 1996, Don Robert’s wife wanted to buy a four-wheel-drive jeep. She called him from a dealership in southern California to say she was being offered a cheap financing deal if their credit score was more than 700.

Robert was surprised. “I thought: Holy shit. If car dealers are talking about credit scores to my cute little blonde wife, we are really on to something here,” he said.

What he was on to was the burgeoning business of credit rating, the secretive process that scores you financially and can determine if you get a personal loan or mortgage.

Ten years on, Robert is bringing Experian, the huge American credit-checking and business-services group that he heads, to England and a flotation next month on the London Stock Exchange.

Experian is being demerged from its parent company, GUS, the conglomerate that also owns the retailers Argos and Homebase. Its newly independent chief executive will preside over a company with revenues of more than $3 billion (£1.6 billion) that analysts estimate will be valued between £7 billion and £9 billion. Experian looks set to become one of the 50 largest companies on the London market, adding its chief to the ranks of high-profile Americans running British businesses.

Experian is best known as the world’s largest credit-scoring agency, but its reach has expanded. It now deals in all sorts of valuable, and often highly sensitive, financial information — offering its services to corporate clients and, increasingly, to consumers.

A typical retail transaction — say, buying a camera — could be affected by half-a-dozen of Experian’s businesses. For example, its Foot Fall division could help a retailer choose the best location for a camera store. Two other businesses — Simmons and Vente — might help the retailer select its product ranges. Clarity Blue could identify consumers most likely to respond to advertising. And the customer could end up paying for the camera with a credit card approved after Experian’s credit checks.

Much of Experian’s business is done anonymously for big clients such as American Express, HSBC and Vodafone. Until recently Experian was overshadowed by its less remunerative but far more glamorous stablemate, Burberry. GUS demerged Burberry in 2005 and the clothing and accessories company has gone on to have a successful, if sometimes rocky, solo career.

Robert is confident that Experian can also bloom away from its parent and is looking forward to the London move. “Not many people get the opportunity to live and work in another country,” he said, adding that London was ideally situated for a global business — it is halfway between the developing markets in the east and North America.

But he is wary of the exposure the demerger will bring. “My job will change for the worse,” he said. “We have been shielded to a great extent by GUS. It will be a big change being a public company.”

Robert, 47, joined Experian as chief operating officer in 2001 from First American, a business-information group, becoming chief executive of North America in 2002 and global chief in 2005.

He has concentrated on making sure Experian’s businesses act as one. “Five years ago, if American Express called a meeting to get information, many of the Experian people would see each other for the first time at that gathering. It was very, very embarrassing.”

When he took over, Robert called in his top 15 sales people and charged them with making sure the company got better at meeting clients’ needs.