According to people with way more time and brains than us, the damage caused to New York in the first Avengers movie was around $160 billion. What's really depressing about that number, though, is that roughly zero percent of it would be covered by anyone's insurance.
And zero percent covered by Stark Industries. 'Cause shawarma and scotch aren't going to pay for themselves.
Some policies may insure limited "Acts of God," but that really only covers Thor's mis-thrown hammers. And even if someone wanted to argue that the Chitauri invasion was a terrorist attack, then that still wouldn't mean shit, because casualty and property insurance almost never cover terrorism. That all would have to change after the first real-life supervillain massacre.
Good luck suing the terrorists for damages when their mailing address is billions of light years away.