Markets sold off big across the board Thursday for their biggest one-day loss in nearly two months. The Dow ended down 264 points, the S&P 500 lost 32 points, and the Nasdaq was hit the hardest, closing almost 2% lower. Tech stocks led the downward spiral. Apple (AAPL) steered the Nasdaq's declines. The stock is getting punished for its problems with the latest iPhones and software. Dow component Microsoft (MSFT) also lost about 2%. All the blue chips ended the session in the red. JPMorgan (JPM) along with UnitedHealth (UNH) were its worst performers, all down more than 2%. But PNC's (PNC) Wealth Management's Chief Investment Strategist Bill Stone says not to panic about this selloff. He says 'the pullback today looks like a bit of profit taking primarily driven by global jitters rather than any disturbing domestic news.'