I don't mean this as in the financial reason Stark needed to sell it but how does Stark get to sell it?
I know it was rebuilt a couple times but just prior to Secret Wars it was seized by SHIELD and under their control. It was apparently destroyed again right before Secret Wars but the city was rebuilt as if the incursion never happened. So shouldn't SHIELD still own the building following Secret Wars? SHIELD still has connections to The Avengers and SHIELD still operates within New York. Why on Earth did SHIELD just pack it all up once the incursions had been over and why would they just let Tony own the building after his actions on the west coast. Even if he was inverted that is still something people can and should hesitate about. Especially since he was also based in the west coast prior to Secret Wars. Why did he come back? He wasn't present as well during Rage of Ultron and it was his building getting assaulted by Ultron. He wasn't even on the Avengers and apparently hasn't prior to ANAD Avengers so why did he get the building if he wasn't funding them and had no control over the building prior to this?