The U.S. Federal Reserve's monetary stimulus reduction and China's economic slowdown were selected as major systemic risks to South Korea's financial system, a survey by the central bank here showed Tuesday. The Fed's tapering of bond purchases topped the list of five core systemic risks with 77 percent, followed by China's slowdown with 72 percent and household debt problems with 70 percent, the Bank of Korea (BOK) said in the poll for the first half.