Iron Maiden have never been exactly fashionable: too mainstream for punk, too scruffy for New Wave, too hairy and loud for pop. But it seems the classic British metal act is very good at turning metal into gold.

In a report published on Friday by the London Stock Exchange, the group – formed in Leyton, east London in the 1970s – has been cited as one of the UK's fastest growing music firms, helping to pull the UK from economic heart failure into recovery.

Iron Maiden LLP, the group's holding company, is one of six music firms at the vanguard of the new music business, according to the report entitled 1,000 Companies to Inspire Britain.

The group has been ranked in the music category of the report alongside digital newcomers, such as app-creators Shazam whose musical pedigree is a little less tried and tested. Publishers Kobalt Music Group and the production music library Audio Network also made it into the list, albeit with fewer riffs and less impressive hair.

And it appears that the band – consisting of founder, lyricist and bassist Steve Harris, 57, 56-year-old guitarists Dave Murray, Adrian Smith and Janick Gers, 55-year-old vocalist Bruce Dickinson and 61-year-old drummer Nicko McBrain – have done it in the traditional way, using old fashioned graft and relentless touring.

On the back of 109 days of touring, which saw the band perform 46 shows in 24 countries (their crew drinking 5,646 bottles of Trooper beer and eating 96 wheels of cheese) for their Maiden England World Tour – Iron Maiden saw their international fan base grow by five million online fans, according to Musicmetric, with a vast number of them from South America.

Greg Mead, CEO and co-founder of Musicmetric, said: "Iron Maiden's BitTorrent data suggests Brazil is a huge driver of fans – and given Brazil is one of the biggest file sharing nations on the planet, this is a strong indicator of popularity.

"With their constant touring, [the] report suggests Maiden have been rather successful in turning free file-sharing into fee-paying fans. This is clear proof that taking a global approach to live touring can pay off, and that having the data to track where your fan bases lie will become ever more vital."

According to Tom Gilbert, from the London Stock Exchange, the report, while clearly championing Iron Maiden, gives a sign-of-the-horns salute to the often overlooked small- and medium-sized businesses fuelling Britain's tentative economic recovery.

Rather than measuring profit or revenue, the list – which also includes Scottish brewery BrewDog, online printer Moonpig, and Hunter wellies – also looked for steady profit over four years, strong email traffic, boosts in employee numbers and other signals such as the number of patents registered or contracts won.

"A lot of people think of the stock exchange as the FTSE 100, but the vast majority of companies in the UK are small- or medium-sized, and their success is something of an unreported story," Gilbert said.

"Over the last few years the biggest blue-chip companies have in fact produced very few net jobs, that jobs recovery has come from small- and medium-sized companies." And business-savvy heavy metallers, obviously.