Turning 50, divorcing Guy Ritchie and controversy over her recent attempt to adopt Mercy, a four-year-old orphan from Malawi, doesn't seem to have dented Madonna's fortune – or her bankability. Robert Sandall investigates the business of being a Material Girl.

She flagged herself in her 1985 hit as a Material Girl and what a prophetic hook that turned out to be. After last year’s box-office receipts had all been added up, it was revealed that the highest earning pop star on the planet in 2008 was, yet again, Madonna. She grossed more than $371million, nearly all of it on her Sticky & Sweet world tour – more than twice what Coldplay, the hottest rock band on the road at the time, made from theirs.

This remarkable result went almost unnoticed outside the entertainment trade press. We seem to have got used to the phenomenon that is Madonna Ciccone, now a 50-year-old mother of three who, defying all pop’s laws of obsolescence, is still at the top of the greasy pole after 26 years in the game. We don’t seem to mind paying the eye-watering prices she charges to watch her perform these days, either. The average price of tickets for the next leg of her Sticky & Sweet tour, which kicks off in London in July, is around $400 and some can fetch up to $1000.

If the second leg of Sticky & Sweet repeats the success of the first, it will overtake the Rolling Stones' A Bigger Bang outings to become the biggest earning concert tour ever.

Anyone hoping to have a word with Madonna about her ticketing policy meets a wall of silence. Not talking about money in public is one of the few taboos this canny iconoclast respects.

There’s an incident in the 1991 fly-on-the-wall documentary, In Bed with Madonna, that memorably makes the point. It's when the director Alek Keshishian tries to follow her into the trailer where she is about to have a meeting. "Get out, this is business," she snaps and shuts the door in his face.

The viewer is left marvelling at Madonna’s priorities. Here is a woman who, elsewhere in the movie, rolls around on her mother’s grave, fellates a water bottle for the amusement of various gay members of her entourage, strips on stage and generally affects an air of devil-may-care candour – then baulks at allowing a glimpse of a business meeting.

There have been a lot of such meetings in the past 26 years. In the manner of a successful corporate brand, Madonna has spread herself far and wide. Aside from her creative output – the 14 albums, eight world tours, 19 feature films, scores of videos and the recent series of children’s books, The English Roses – Madonna has been an indefatigable dealmaker.

In 1992, she set up Maverick, a record label with video, film and publishing interests, which she jointly owned with Time Warner until 2004. Since 1989, when she accepted $7million from Pepsi for a TV commercial (which got pulled after one showing for its presumed blasphemy), she has been involved in ad campaigns for BMW, Max Factor, Versace and Gap. Last year, she put her name to a clothing line for the UK retailer H&M.

Then there are the merchandising deals, investments in fine art and property, appearance fees and other income accrued. It’s uncertain exactly how rich she actually is – estimates of Madonna’s worth start at the figure quoted in The Sunday Times Rich List 2008 edition: $601million.

To read more about Madonna's millions, see the June issue of The Australian Women's Weekly, out now.

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