US STOCKS-Futures drop on economic slump worries

* Fears of deepening economic slump roil global markets

* Uncertainty about auto sector aid weighs

* Paulson, Bernanke testimony eyed; PPI on tap

* Yahoo replacing CEO, stock up before the bell

* For up-to-the-minute market news, please click on [STXNEWS/US]

By Ellis Mnyandu

NEW YORK, Nov 18 (Reuters) - U.S. stock index futures slid on Tuesday, signaling that Wall Street will extend a global equity rout fueled by fears that the extent of the global economic slump is worsening.

Uncertainty about the fate of the talks over the desperately needed economic aid for General Motors Corp GM.N and others in the U.S. automobile sector also gave investors pause.

There was also caution ahead of appearances by Treasury Secretary Henry Paulson and Federal Reserve Chairman Ben Bernanke on Capitol Hill, who will report on the status of the government's $700 billion financial sector bailout.

In earnings news, Home Depot Inc (HD.N), the largest U.S. home improvement chain, posted a 31 percent slide in third-quarter profit before the bell and forecast a steeper drop in full-year sales than it had previously forecast.

Lower oil prices looked set to drag on energy shares as investors worried a faltering global economy will curb energy demand. U.S. front-month crude CLc1 fell below $55 a barrel.

"It's a foregone conclusion that we're in a global recession. The markets are telling you that and the biggest fear is further labor market deterioration," said Andre Bakhos, president of Princeton Financial Group in Princeton, New Jersey. "Without clarity on General Motors, the market is only going to drift lower."

S&P 500 futures SPc1 were 13.20 points lower and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures DJc1 slid 114 points, and Nasdaq 100 NDc1 futures declined 20 points.

The diminishing appetite for riskier assets sent stock markets across Asia tumbling overnight, with the Hang Seng index .HSI down more than 4 percent, while in Europe benchmark indexes dropped about 2 percent.

Executives from the three biggest U.S. automakers -- GM, Ford Motor Co (F.N) and Chrysler -- head to Washington later on Tuesday to plead their case for government aid.

The White House on Monday opposed Senate Democrats' proposal for a $25 billion bailout for the U.S. auto industry and urged instead that aid be provided through government loans already appropriated for the industry by Congress. For details, see [ID:nN17529264]