UNITED States stocks have fallen for a third straight week, the longest streak since August, after forecasts from AT&T Inc, American Express Co and Tiffany & Co bolstered speculation that the six-year economic expansion is ending.

AT&T dropped the most since 2003 on the New York Stock Exchange after saying customer demand weakened. American Express had the steepest loss since September 2001 after adopting a "cautious view" for the year. Tiffany tumbled the most in 5 1/2 years on slower holiday sales. Goldman Sachs Group Inc economists said the US may already be in a recession, joining counterparts at Morgan Stanley and Merrill Lynch & Co.

The Standard & Poor's 500 Index fell 0.8 percent to 1,401.02 last week, bringing its year-to-date loss to 4.6 percent for the worst start since 1982, according to Bloomberg News data. The measure fell to an almost 10-month low last Tuesday. The Dow Jones Industrial Average sank 1.5 percent to 12,606.30. The Nasdaq Composite Index declined 2.6 percent to 2,439.94.

'Still unknown'

"We certainly have another couple of months to go before we see the bottom of this thing," said Richard Weiss, who helps manage about US$60 billion as chief investment officer at City National Bank in Beverly Hills, California. "The duration of the downturn is still unknown."

AT&T fell 6.6 percent to US$38.20 last week for the third-largest decline in the Dow average behind American Express and Alcoa Inc Chief Executive Officer Randall Stephenson said slowing economic growth led to "softness" in the home-phone and Internet businesses.

American Express retreated 10 percent to US$44. The third-largest US credit-card network reported a US$275 million charge amid signs the housing slump is spreading to consumer spending. December cardholder spending slowed and delinquencies rose, particularly in California, Florida and other areas affected by the housing slump, Chief Executive Officer Kenneth Chenault said in a statement.

Tiffany, the world's second-largest luxury-jewelry retailer, dropped 13 percent to US$35.80. A drop in holiday sales prompted the company to cut its profit forecast and consider lowering 2008 targets.

Tiffany led merchants in the S&P 500 to a 3.3 percent drop. Gap Inc fell 13 percent, the most since August 2004, to US$17.20. Sales at US stores open at least a year rose 2.2 percent in November and December, the smallest rise in five years, the International Council of Shopping Centers said last Thursday.

"It's very difficult to kill the consumer," said Lawrence Creatura, who helps manage about US$2.6 billion at Clover Capital Management Inc in Rochester, New York. But "with declining home prices, and the contraction in credit, and an increase in unemployment and an increase in the cost of living, we're going to find out if we can kill the consumer."