Wall Street's employment tsunami, most recently swamping Citibank Inc, is also undermining the island of Manhattan's 443 million square foot office market, threatening to drag rents down 35 percent from a second quarter 2008 high.

The bankruptcies and buyouts of Wall Street giants Bear Stearns, Lehman Brothers and Merrill Lynch, and the massive layoffs implemented by survivors such as American International Group Inc <AIG.N> and Citi will shrink the Street -- and its need for office space.

'The pendulum has swung completely the other way from being a landlord's market to being a tenant's market,' said Steve Chasanoff, a director at FirstService Williams, a real estate services firm.