IT IS one of America’s biggest family firms, with revenues last year of more than $30 billion. Yet unlike peers such as Mars, a maker of confectionery, Pilot Flying J is all but unknown overseas. And it is more reclusive than other private family groups such as, say, Koch Industries, a conglomerate headed by Charles and David Koch.

Pilot Flying J’s business, operating filling stations on America’s highways, focuses mainly on a narrow group of customers: lorry drivers. It has little need to make itself known except among those knights of the road. Furthermore, the company has been recovering from the biggest scandal in its history, making it more taciturn than ever.

In 2013 the FBI raided its headquarters in Knoxville, Tennessee. An affidavit unsealed by a federal judge accused individuals at the firm of running a scheme for at least five years to swindle small haulage firms out of millions of dollars in rebates on purchases of fuel. (For small firms, discounts were calculated manually, which facilitated the cheating.) According to the affidavit, an informant told the FBI that Jimmy Haslam, Pilot Flying J’s chief executive, knew about the scheme. Mr Haslam has steadfastly denied any knowledge of fraudulent practices. The company did not respond to our repeated requests for an interview or to e-mailed questions.

The accusations shook the Haslam family. Until then it had been a textbook example of the American dream come true. Its patriarch, “Big Jim” Haslam, the father of Jimmy, founded Pilot in 1958 when he paid $6,000 for a filling station in Virginia. The firm grew rapidly over the years, mainly through acquisitions of smaller truck-stop chains and independent operators. Its biggest deal was the takeover in 2010 of the bankrupt Flying J chain, for $1.8 billion.

Today Pilot Flying J is the biggest in an industry dominated by three firms that together have around two-thirds of the market: the others are Travel Centers of America, a public company based in Ohio, and Love’s, another family firm, from Oklahoma. Jimmy Haslam and his brother Bill, who is the governor of Tennessee, appear regularly on lists of America’s richest. Thanks to their philanthropy the clan has made many friends, especially in Tennessee, where even the lion cubs at the Knoxville zoo were named after Haslams.

In the 1970s the company realised that its roadside sites could lucratively double up as convenience stores. Today a typical Pilot stop in Michigan, for instance, still in retro brownish decor, sells anything from sweets and toys to DVDs and mugs. More than 400 of the firm’s 678 stops also house a fast-food franchise, such as Subway or Arby’s. The margins of the non-fuel businesses are higher than those from selling diesel and petrol, but it’s the pumps that pull in the punters. Around 90% of Pilot’s revenue comes from fuel, but close to half of its gross profit is generated by non-fuel sales. Pilot is also meticulous about the cleanliness of the stops’ showers, which encourages truckers to stay loyal.

On the rare occasions when the Haslams speak about their business, American-football metaphors tend to come up. Big Jim, once an avid football player at the University of Tennessee, has said that he used his university coach’s maxims to beat his business rivals. One of them is that “The team that makes the fewest mistakes will win.” Another is “If the game goes against you…put on more steam.” Jimmy is even more football-obsessed. In 2012 he spent a chunk of his fortune to buy the Cleveland Browns, a successful team.

When the game went against him in 2013 he needed his father’s maxims more than ever. After the FBI raid, the firm’s lenders and suppliers were nervous about the potential for gargantuan penalties, compensation payments and an exodus of clients. However, Pilot put on more steam, and cleaned up its mess relatively quickly. In November 2013 it paid $85m to settle a class-action lawsuit launched by more than 5,500 hauliers who had been short-changed on their rebates. A few companies continued to pursue separate lawsuits, of which one is still pending. In July 2014 Pilot accepted responsibility for the criminal conduct of its employees and paid the Justice Department a fine of $92m.

Its prompt actions to put things right meant that most of Pilot’s users stayed loyal to the company, says Ben Bienvenu, an analyst at Stephens, a financial-services firm. The same was true for most of its suppliers and lenders. “They are on a stable financial footing now,” says Manoj Chadha of Moody’s, a credit-rating agency. The company also made lots of changes to prevent a repeat of the rebate scandal. According to Samantha Stone at Standard & Poor’s, another rating agency, the sales team at head office was largely replaced, all transactions have been automated and customers can now demand that an independent auditor review their rebates.

As it has cleaned up after the scandal, Pilot has also benefited in the past couple of years from the slowly recovering economy and the slump in oil prices, both of which have lifted demand for fuel. The firm will remain on the lookout for smaller rivals that it can swallow. It costs on average $9m to take over and renovate an existing filling station at a good location, but between $14m and $20m to build one from scratch, explains Bryan Maher of FBR, an investment bank in Virginia. Greenfield developments are slow and tricky because of environmental and safety regulations.

Pilot Flying J was lucky that the rebate scandal did not erupt during the recession, when fewer lorries were on the road and the company, like its main rivals, was suffering losses. Its efforts to rebuild its reputation coincided with a boom in its business. The firm seems to have turned the page. Today the headlines about Jimmy Haslam are mostly related to the changing fortunes of the Cleveland Browns.