US STOCKS-Futures slump; Dow, S&P may turn negative for July
* Investors fret over Argentina default fallout
* Exxon, Whole Foods both fall after results
* Jobless claims rise more than expected in latest week
* Futures down: Dow 132 pts, S&P 16.5 pts, Nasdaq 35.25 pts (Updates prices, adds jobless claims data)
By Ryan Vlastelica
NEW YORK, July 31 (Reuters) - U.S. stock index futures pointed to a sharply lower Wall Street open Thursday, with the Dow and S&P 500 likely to turn negative for the month on concerns over the strength of overseas economies and ongoing tensions with Russia.
* Data showed U.S. jobless claims rose more than expected in the latest week, a discouraging sign on the labor market ahead of the closely watched July payroll report on Friday.
* Portugal's Banco Espirito Santo's slumped almost 40 percent to an all-time low as the bank's hopes of raising capital without taking state aid suffered a major blow following massive losses.
* In Russia, Moscow fought back over new U.S. and EU sanctions that had been imposed over Ukraine, announcing a ban on most fruit and vegetable imports from Poland. Continuación...