I've tried crunching the numbers on the tour plenty of times. It isn't the most profitable tour U2 have done, but it is profitable.
Here's my take on the numbers.
The tour lasted roughly 120 days last year at a cost of $750,000 a day. This comes out to $90m in total operating costs for the year.
I'm guessing the tour startup costs at around $70m based on what I've read about the cost of building the 3 claws and the fact that they undertook rehearsals with the actual stage setup in the venue for a few weeks prior to the start of the tour.
This means a total cost of $160m for the tour last year.
In terms of income, I think U2 probably used a guarantee plus percentage fee structure for the tour.
I'm taking a big guess and saying, based on the cost of the tour and the expected gross, that they negotiated a guarantee of $3.5m per show or $154m in total (paid by Live Nation) as well as 90% of the gross per show after allowed deductions.
The allowed deductions would include the guarantee plus any other cost incurred by Live Nation in putting on each show. I'm estimating these other costs at $1.5m per show. Then Live Nation has probably also negotiated a guaranteed profit margin of 15% so that means that total deductions are $3.5m + $1.5m x 1.15 or $5.75m.
With an average gross of $7.068m per show, this leaves $1.318m of which U2 takes 90% or $1.186m.
This gives U2 total percentage earnings of about $52m, which when aded to the total guarantees of $154m, gives total income from the tour for U2 of $206 million (the remainder of the gross goes to Live Nation, the venue etc).
$206 million minus the total expenses of $160 million give U2 a profit for the tour of $46m not including merchandise sales, sponsorship etc.
This works out to around 15% of the total gross, which is a bit lower than the 25-35% profit margin that I've read is common for large, high overhead tours.
The profit for this year will probably be even lower as even though, U2 don't have any startup costs this year, the running costs are the same and they are playing smaller venues, with a only about 2 shows being played a week, which will eat away at their profits.
I should also say to take all of my figures with a few grains of salt. I'm no expert on these things, I just have too much time on my hands. I'm only guessing and I could be completely wrong. so don't take them too serously.
Hope that helps.