how do you find out who your building was sold to?

[clearday]

Our building was just sold, we were told by the super and the restaurant in the building, but we don't know who the new landlord is or anything about his/her company. How can we find out?

[consigliere]

The owner that sold the building should inform the tenants of the sale and let them know the name and address of the new owner.
 
Since that hasn't happened, you should write to the old owner, by certified mail, and tell him/her that you have heard that the building was sold, and ask for the name and address of the new owner.
 
I wouldn't rush to pay rent to the old owner, who might not turn it over to the new owner, who might then demand the same month's rent from you.