“At the moment there is a readiness to believe the worst,” said Simon Williams, HSBC bank’s chief economist in Dubai. “And the limits on data make it difficult to counter the rumors.”

Some things are clear: real estate prices, which rose dramatically during Dubai’s six-year boom, have dropped 30 percent or more over the past two or three months in some parts of the city. Last week, Moody’s Investor’s Service announced that it might downgrade its ratings on six of Dubai’s most prominent state-owned companies, citing a deterioration in the economic outlook. So many used luxury cars are for sale , they are sometimes sold for 40 percent less than the asking price two months ago, car dealers say. Dubai’s roads, usually thick with traffic at this time of year, are now mostly clear.

Some analysts say the crisis is likely to have long-lasting effects on the seven-member emirates federation, where Dubai has long played rebellious younger brother to oil-rich and more conservative Abu Dhabi. Dubai officials, swallowing their pride, have made clear that they would be open to a bailout, but so far Abu Dhabi has offered assistance only to its own banks.

Image A car salesman in Dubai on Wednesday sat without customers. Lack of credit and a glut of cars on the market are cutting sales. Credit... Bryan Denton for The New York Times

“Why is Abu Dhabi allowing its neighbor to have its international reputation trashed, when it could bail out Dubai’s banks and restore confidence?” said Christopher M. Davidson, who predicted the current crisis in “Dubai: The Vulnerability of Success,” a book published last year. “Perhaps the plan is to centralize the U.A.E.” under Abu Dhabi’s control, he mused, in a move that would sharply curtail Dubai’s independence and perhaps change its signature freewheeling style.

For many foreigners, Dubai had seemed at first to be a refuge, relatively insulated from the panic that began hitting the rest of the world last autumn. The Persian Gulf is cushioned by vast oil and gas wealth, and some who lost jobs in New York and London began applying here.

But Dubai, unlike Abu Dhabi or nearby Qatar and Saudi Arabia, does not have its own oil, and had built its reputation on real estate, finance and tourism. Now, many expatriates here talk about Dubai as though it were a con game all along. Lurid rumors spread quickly: the Palm Jumeira, an artificial island that is one of this city’s trademark developments, is said to be sinking, and when you turn the faucets in the hotels built atop it, only cockroaches come out.