This sale was posted by Trulia - not a broker or agent. It's their way of providing sales info for the public.
If you want to know how much your co-op could sell for, and want to sell it now, you should find a real estate agent to help you. And if you are thinking of selling a co-op on your own, you should definitely find an agen, because a criteria for pricing a co-op is generally not by the number of shares owned. Location, sq.ft., and the condition of the unit and building are much more important.
Sally Griffiths, GRI
Licensed Associate Real Estate Broker