There is not enough info in your question to give a good answer. We would need to know the exact building you are talking about. Also, the words "a lot" can be a matter of perception. As an example, I am selling a unit in the co-op building located at 1170 Ocean Parkway. There are about 7 units for sale in that building. Some people may thin that is a lot, but relatively speaking it is not that much. At 1170 Ocean Avenue there are about 160 units in the building so having 7 up for sale at any given time is not a lot. If you have a 28 unit building with 7 units for sale then that would be cause for concern.
Often times co-op building may have what you call a sponsor. This is a private investor who owns many units in the building and usually rents them out. Sometimes the sponsor (not all building have one) will decide to sell one, some or all of their units. If that is the case you may see several or many units for sale in a building. That in and of itself would not indicate that there is a problem in the building.
When purchasing a co-op your main concerns are the following:
1) How many units are sponsor owned? If too many units are sponsor owned a bank may not be willing to give a mortgage on a unit within the building.
2) What is the financial condition of the building? Your lawyer will review the co-ops last two or three years financial statements to make sure they are financially healthy.
3) Are you familiar with the house rules? Some buildings do not allow subletting or pets, make sure you are aware of the house rules.
4) How much is the flip tax? Flip tax is a fee the SELLER pays to the co-op when they sell, if it is too high you may have a problem getting the mortgage, look into that. Also keep in mind that you will pay the flip tax when and if you sell.
5) What is the overall size, condition, location of the co-op? These factors will effect the ultimate value now and when you sell it.
6) What utilities does the maintenance include and how much of my monthly maintenance is tax deductible? These item will effect the affordability of the co-op for you.
If I can be of further assistance please let me know. Good luck!
Mitchell S. Feldman
Associate Broker/ Director of Sales
Madison Estates & Properties, Inc.
Office: (718) 645-1665/ Cell: (917) 805-0783