Chen Kuo-min explains that "ninety-eight" refers to the turn-around selling of local goods in Southeast Asia. Because those in this middle-man trade took only 2 percent commission, they become widely known as "ninety-eights."
陳國民解釋，九八行是指東南亞土產進出口買賣；因為這行只抽百分之二的佣金，一般俗稱「九八」。