Stocks and exchange traded funds (ETFs) were battered today, starting off the morning on a down note and remaining there.

The International Monetary Fund (IMF) came out with a downbeat report that didn’t help matters, saying that the U.S. economy’s growth would be close to zero or negative for the first few months in 2009, reports CNN Money. The IMF also predicts a continuing global downturn, with growth falling to its slowest pace since 2001-2002, thanks to the credit crisis and volatile commodity markets.

The Dow Jones Industrial Average closed down today more than 500 points on a host of concerns about the economy.

Particularly alarming for investors was Yahoo (YHOO), which said yesterday that it would lay off 1,500 workers – about 10% of its entire workforce, reports Miguel Helft for the New York Times. The company said that reduced marketing budgets ate away at its online advertising business and sending its net income for the third quarter down 64%.

AT&T (T) reported higher profits, but the 5.5% gain still missed Wall Street estimates, reports Peter Svensson for the Associated Press. iPhone subsidies ate into profits, which work out to about $375 per unit. AT&T says that the subsidies will even out over time as iPhone users are voracious data consumers and pay 60% more in service fees than owners of other phones.