South Korea's brokerage houses slashed their fourth-quarter earnings outlook for domestic listed firms this month, data showed Tuesday, due mainly to the prolonged slump in the local economy. The operating-profit outlook for firms listed on the main bourse came to 34.4 trillion won (US$32.1 billion) for the October-December period as of Tuesday, down 4.4 percent from an estimate made a month earlier, according to the data compiled by SK Securities Co.