A lower start for Wall Street

NEW YORK (CNNMoney.com) -- Stocks took a knock at the start of trading Thursday as investors fretted about continued weakness in the U.S. economy.

The Dow Jones industrial average fell 0.8%. The Nasdaq composite index retreated 0.5%. The Standard & Poor's 500 index pulled back 0.5%.

In the news Thursday:

GDP revision: A revised reading on gross domestic product showed no change in the anemic 0.6% annual economic growth rate previously reported for the fourth quarter.

Sprint: The struggling telecom posted a fourth-quarter loss of $29.5 billion, or $10.36 a share, reversing the year-earlier profit of $261 million, or 9 cents a share. The latest quarter was hit by a $29.7 billion writedown of merger-related goodwill, reflecting the difference between the price Sprint paid and the actual value of the assests purchased. Stock (S, Fortune 500)

Sears Holdings: The department store retailer controlled by Chairman Edward Lampert said fourth-quarter profit tumbled 47%, due to poor performance at its Kmart and U.S. Sears stores. Stock (SHLD, Fortune 500)

Freddie Mac: The mortgage backer said its loss widened to $2.5 billion in the fourth quarter of 2007 as defaults mounted on home mortgages and it set aside cash in expectation of further losses. Stock (FRE, Fortune 500)

Alcoa: The U.S. aluminum maker bribed, overcharged and extracted "hundreds of millions" from a company owned by the Persian Gulf state of Bahrain, according to a federal lawsuit seeking more than $1 billion from the company. Stock (AA, Fortune 500)