Update on Sept 22, 7:20 pm PST: AEG released the following statement in response regarding the end of the Osbourne lawsuit:

On Friday, Ozzy Osbourne dismissed the class action lawsuit he filed against AEG.  This dismissal with prejudice is a victory for AEG.  We were fully prepared to see the case through to vindicate our policy, but now that Osbourne has decided to dismiss with prejudice, the case is over.
 
Our policy was an appropriate, lawful and effective competitive response to Irving Azoff’s pressure tactics seeking to force artists into the Forum.  If those tactics resurface, we will redeploy our policy as needed.
 
The Osbourne suit was instigated by Azoff and paid for by MSG and Live Nation.  It was hatched on the back of an artist who we believe had no idea what he was biting off.  The suit was a transparent public relations ploy that failed to pressure AEG into backing down from a booking policy that was an effective competitive response to the MSG-Forum tie. 
 
It is no surprise that once AEG refused to back down, Azoff, MSG and Live Nation became eager to drop the case as soon as possible.  They dismissed the case with prejudice after realizing AEG would aggressively defend it, costing them tens of millions of dollars and posing a source of embarrassment once their questionable tactics were exposed in the course of discovery and trial.

The legal battle between Ozzy Osbourne and AEG has come to a close, with lawyers for the Black Sabbath frontman agreeing to drop a lawsuit against AEG after company officials announced plans to end its policy requiring acts that wanted to play the O2 Arena in London to also play Staples Center in Los Angeles.

On Friday afternoon (Sept. 21), Ozzy's attorney Dan Wall filed a stipulation to dismiss the case before U.S. District Court Judge Dale Fischer, a procedural move that brings an end to the anti-trust lawsuit filed in March against AEG. The case was dismissed with prejudice, meaning Osbourne can't refile the lawsuit.

"Sharon and Ozzy are pleased, there is nothing left to litigate," Wall tells Billboard.

Osbourne and his wife and manager Sharon Osbourne allege the singer had requested a February 2019 hold for the O2 Arena for his No More Tours 2 farewell tour. Osbourne's attorney alleged that Ozzy was negatively affected by a requirement that tour promoter Live Nation sign the Staples Center Commitment Letter, requiring Osbourne to play the AEG-owned Staples Center at least once if Osbourne planned to play a large indoor show in Los Angeles.

Osbourne sued, seeking an injunction to prohibit AEG from enforcing the commitment letter and sought class-action status for other artists affected by the policy. Officials with AEG said they enacted the block-booking requirement in reaction to what they allege was block-booking between the Forum and Madison Square Garden, a claim Irving Azoff with Azoff MSG Entertainment denies.

In August, Judge Fischer denied AEG's motion to dismiss the case, rejecting AEG attorneys' argument that Osbourne​ wasn’t a party to the agreement his promoter Live Nation and AEG had and therefore didn't have standing to sue.

"Because Ozzy’s only reasonable choice of venue in London is the O2 Arena, he is explicitly coerced by a contract that says he must play the Staples Center,” Judge Fischer wrote, adding, "Ozzy personally suffers damage in a fairly direct and non-speculative way by not being able to play in his preferred venues.”

Six weeks later, AEG chief executive Jay Marciano announced he was ending the block-booking policy, telling Billboard "promoters for artists that want to play the O2 will no longer be required to commit to playing Staples Center," adding, "Going forward, we will only require this commitment if we believed artists were being pressured to play the Forum to gain access to the Garden."

The change in policy meant the unofficial end of the lawsuit, and nine days later, Osbourne's attorney filed to have the case dismissed.