What's up with the apts on 7th ave??

Subject: What's up with the apts on 7th ave??

Does anyone know about the (prewar?) apts on 7th ave around 14th/15th steets? I've noticed about 5 postings for them being sold by owner on various sites online. The area is nice, but why are so many people in what appears to be the same building selling all at the same time and none are using a broker?
If it was two ads, I'd think one person decided to sell and another saw how much they could potentially get and jumped on board and did not want to use a broker thinking they could sell on their own. But since there are a bunch of them, it seems highly suspect.

Thoughts? Insider info?

Thanks

B.P.