It would have to be a worldwide bear market.There are five major cities...London,Hong Kong,Singapore,Dubai and New York....that attract breathtaking sums of money from all over the world.Every Saudi prince,every Hong Kong factory owner,wants a place (or five) in London or Manhattan.I was just in Dubai,for example,a few months ago.You wouldn't believe the money...from near and far...that you'll find in that city.And Manhattan's no different.
Manhattan is very different. It depends very specifically on US Government Debt, the role of the US dollar as the world's reserve currency, and above all, the Federal Reserve's ZIRP and pumping of the US stock market. I don't see NY City having any other economic advantages whatsoever.
(raising money for Romney? lol)