NEW YORK (TheStreet) --The Dow Jones, NASDAQ, and S&P 500 all closed in the red on Thursday. Today marks the eighth straight day of declines for the S&P 500, its longest losing streak since 2008.

"We're actually only 5% off of the historic highs it was about 2,180 back in August," CNBC's Bob Pisani said during this afternoon's "Closing Bell."

The major hit on the S&P today, he explained, were reports that several healthcare providers and drug producers could face potential charges regarding pricing from the Department of Justice.

"That's a big thing there. We're not talking about companies that are very specific drug producers, we're talking about generics now in a potential investigation, that just tanked the S&P 500," Pisani explained.

Also underperforming is the REIT sector. "In the last five to six days we've seen retailers moving to the downside," Pisani said.

The final substantial problem impacting the markets Pisani noted was oil, as it has seemingly "de-coupled" from the rest of the market.

"Oil is down more than 10% in the last five or six trading sessions yet the rest of the market, while gently down, not in a big way," Pisani added.

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