US stocks slumped, yesterday, with banks taking the biggest losses. Deutsche Bank hit an all-time low as investors worried about the financial health of Germany's largest bank. The U.S. presidential debate between Democratic nominee Hillary Clinton and her Republican rival Donald Trump also contributed to jittery investor sentiment. Pfizer pulled pharma firms down after it announced that it will not break up into two companies. So the Dow Jones industrial average dropped 167 points, or 0.9 percent, to 18,095. The Standard & Poor's 500 index slid 19 points, or 0.9 percent, to 2,146. And the Nasdaq composite lost 48 points, or 0.9 percent, to 5,257.