Almost certainly a corporate rate - looking at the RC Battery Park the rate shows up with 'must book through designated travel agency' which is an odd thing to say otherwise.
On the other hand, the rate there is pretty crappy by comparison with my corporate rate - and that rate shows up with "Please be prepared to show proof of eligibility for your rate ... " in the rate rules
I just can't see the attraction of using corporate codes to which you're not entitled (or, equivalently, you don't know enough about to know if you're entitled).
So you see a fantastic rate online using XYZ code, then you turn up and they've canceled your reservation because you didn't book through the approved travel agent for XYZ Corp. You end up paying the walkup rate.
Or you get to reception and they ask to see your XYZ Corp identity card or business card; you bluff that you're visiting XYZ's office on Wall Street and they asked you to use this corporate code. Maybe you get lucky; maybe they insist that this code is strictly for XYZ staff and make you pay the walkup rate.
It's such a lottery and a pretty stressful way to start a vacation or a business trip.