On one level, the stock that you own in your co-op is no different from the stock that you might or could own in Google or Apple. Your co-op is a corporation probably governed under New York State Business Corporation Law (BCL), the very same law that governs most New York business corporations.

Also, the co-op stock that you own is, in some sense, publicly traded. The brokers in either case would broadcast the availability and terms of sale of such stock to the public at large (although they do so, of course, by very different means, with real estate brokers using property-listing sites and stock brokers using stock exchanges and the over-the-counter market).