Take a look at Forbes' newly published list of the world's top-earning musicians, and you'll notice something interesting. Many of the list's top names haven't released any new music recently.
Rock stalwarts U2 and AC/DC top the chart with respective earnings of $130m and $114m, while relatively new acts like Lady Gaga ($62m) and the Black Eyed Peas ($48m) also appear.
Beyoncé is #3 in Forbes' list,
But Forbes' chart isn't only useful for seeing how wealthy the world's richest musicians are. If you read between the lines, it also offers clues to how they're earning their money. And the list has great connotations for the collectors' markets.
Like Beyoncé Knowles, for instance. The US R&B sensation is #3 on Forbes' list with total earnings of $87m. Yet her only new music releases in 2010 were one single, back in August, and a guest appearance on Lady Gaga's hit song, Telephone.
In fact, Beyoncé hasn't released a new album proper for almost two years: November 2008's I Am... Sacha Fierce. Meanwhile, U2's last full-length, No Line On The Horizon, came out in 2009 and they haven't had a single out since September of that year.
While the world's top-earning musicians aren't releasing any music, major music labels around the globe are suffering declining record sales and an increasing number of fans illegally downloading music for free over the internet.
So where are the world's top musicians earning their millions?
For answers, look no further than the world's stadiums. While Beyoncé has been absent from the charts, her I Am... World Tour has been raking in millions across the globe through ticket sales and tie-in merchandise.
Ditto U2: if you think Bono's band has been keeping a low-profile recently, then try standing in a stadium with them (although you'll probably have to pay around $55 a ticket for the privilege).
No platform too big: U2 perform on the largest concert stage ever
There, you'll be confronted by the largest '360°' concert stage ever constructed, Bono wearing a laser-embedded suit, and a multi-million dollar profit machine that has been touring the globe since U2's No Line On The Horizon album was released last year.
This is great news for collectors...
There are two reasons why: 1) rather than simply buying CDs, fans are increasingly looking to invest their cash in an event ('the real thing') be that concert tickets or memorabilia; 2) nostalgia... This second point was demonstrated by the #4 name on Forbes' list, Bruce Springsteen (total earnings: $70m).
In contrast to the dwindling sales of CDs, tickets for the Glastonbury Festival are selling out in record time each year. In 2009, Springsteen - or The Boss as he's known to his fans - was one of main headline draws.
Yet most fans weren't there to hear his new material. They wanted to hear The Boss's classics like Born In The USA. Likewise the 100,000 fans in Moscow who queued up to see Sir Paul McCartney play Back In The USSR live.
Buyers around the world are investing in the 'real thing'
Nostalgia and getting closer to the artists are large motivational factors for collectors. So it's no coincidence that as the global live music markets grow, so too are the markets and values for memorabilia and autographs (as shown in the industry's).
If you bought a signed photograph by The Beatles ten years ago for £5,500, it could today be worth £22,500 - that's an increase in value of 309.1%. The Beatles, unsurprisingly, are among the most bankable acts in the collectors markets. So how do the other artists on Forbes' new list compare?
Well, a guitar signed by The Boss sold for sold for $3,450 - above its pre-sale estimate of $1,500-2,500 - at an auction in Pennsylvania earlier this year. It's sure to gain value in future years - which makes Springsteen's autograph a must-see for entry-level investors, currently priced at £200-300.
Elsewhere, a stage costume worn by Lady Gaga sold at auction for £1,300 ($2,000) while one of her pianos has appeared on the market priced at tens of thousands. While Madonna's stage outfits sell on today's markets for as much as £15,000 ($23,035), the same could one day be said of Lady Gaga.
One thing's for sure: as buyers are encouraged to get away from their bedroom CD players and into the world's concert venues, the continuing live music boom is only good news for the collectors' markets.
- Learn how you can get pleasure and profit from guitars and rock 'n' roll memorabilia
- Click here for all the latest Memorabilia and Autographs news
Join our readers in over 200 countries around the world - sign up for your free weekly Collectibles Newsletter today