The Manhattan apartment market, long immune to national trends, could be cooled by the latest credit crunch and its effect on global markets, experts say.

With hedge funds collapsing and a stock market increasingly prone to wild swings, Wall Street bonuses, a major driver of the booming local housing market, could take a hit, especially when compared with the record awards at the end of 2006.

Taken with a hike in mortgage rates from wary lenders and a tightening of lending standards, the seemingly endless demand for Manhattan apartments could drop, putting an end to the rising prices that have characterized the local market for much of the past decade.

“I’ve been doing this 20 years — I’ve never seen anything change this fast,” a vice chairman for the brokerage firm Prudential Douglas Elliman who works with the high-end residential market, Dolly Lenz, said. Buyers feel far less rushed to snatch up apartments, and are taking a more cautious attitude toward buying homes of more than $10 million, Ms. Lenz said.

“The high-end market is one of confidence — it’s pure, pure confidence, and the minute the confidence isn’t there, that’s when the attitude changes,” she said.

In recent years, experts have cited a booming local economy and an increasing population for the constant upward trend in New York City housing prices, which comes while other markets throughout the country have stagnated in the past year or two. Home owners have seen appreciations that may have seemed unfathomable in the 1980s or early 1990s: In the past 10 years, the median price of a Manhattan home has more than tripled, rising to $895,000 from $275,000, according to the appraisal firm Miller Samuel.

In the past two to three weeks, as a number of high-profile hedge funds have collapsed and interest rates for some loans have shot up, a chilling, cautious mood seems to have hit the real estate community, even in Manhattan.

While it’s early to determine the full scope of the credit crunch, some economists say it has the potential to crack into the local market, slowing down purchases at all levels.

“There’s been so many declines in home prices around the country,” an economist at Yale University, Robert Shiller, said. “Of course it could be reversed, but the more probable outcome is that it will continue, and I don’t know that Manhattan can continue to be immune from that.”

Recent concerns about housing prices come as a crisis in the nation’s market for subprime lending, which issues loans to people with poor credit, seems to be spreading to the broader lending market.

A spike in foreclosures at the end of 2006 from homeowners who received subprime loans has created something of a domino effect, causing the collapse of mortgage companies and hedge funds with significant subprime holdings. Now as larger banks are feeling a pinch — two of financial giant Bear Stearns’s hedge funds imploded in recent months — lenders are becoming increasingly reticent to loan money, crimping the availability of mortgages.

Since mid-July, rates have shot upward rapidly for mortgages that exceed $417,000, known as “jumbo mortgages,” which are too large to be backed by the federally chartered Fannie Mae and Freddie Mac financial organizations. Manhattan, with an average sales price of about $1.3 million, is especially prone to the spike in interest rates for jumbo mortgages, which have climbed nearly a half point in the past two weeks alone, according to the financial tracking firm Bankrate.com.

“In a market like Manhattan, where so many of the potential purchases would require mortgages above the jumbo cutoff, it’s inevitable that higher mortgage rates and a higher cost of capital will impact demand,” the senior economist at the real estate research firm Reis Inc., Sam Chandon, said.

Should the tightening market and rise in foreclosures significantly affect the overall performance of the financial sector, demand for apartments in Manhattan would likely decline to some degree, given the industry’s substantial presence in the city. Housing experts say record Wall Street bonuses have had a very strong impact on the rising prices in the city, fueling sales of both luxury and moderately priced apartments.

While financial experts say the diversified portfolios protect the large banking firms from seeing big declines, the potential is there to decrease bonuses, which would likely cause a ripple effect in the Manhattan apartment market.

“They’ve been the catalyst for the elevated level of demand that has been shown,” the president of Miller Samuel, Jonathan Miller, said of the bonuses.

But even if there is a drop in bonus pay and a tightening of the credit market, Mr. Miller said he thinks the demand in Manhattan strong enough to stave off a significant drop in prices.

“The momentum and the strength of the market to date has shown no signs of a highly speculative, tight market,” Mr. Miller said. “I see the credit tightening issue playing out to be a much bigger factor in markets that are already in trouble.”