Stocks extended losses today off the news of a 3.8% decline in US GDP for the fourth quarter, ending a turbulent month, MarketWatch reports. The report capped a week of widespread layoffs and poor earnings at major US firms. Amazon.com was a rare exception, up 18% on strong fourth-quarter earnings. The Dow fell 148.15 to close at 8,000.86. The Nasdaq closed down 31.42 at 1,476.42, and the S&P 500 lost 19.26 to settle at 825.88.