At least one broker is requiring investors to pay cash upfront to buy shares of Serba Dinamik Holdings Bhd. This means the standard practice of the T+2 settlement cycle will not apply for the oil and gas services company for the time being. A source from RHB Investment told StarBiz that Serba Dinamik securities are considered as high-risk. PETALING JAYA: After several rating downgrades and hitting limit-down for two consecutive days, at least one broker is requiring investors to pay cash upfront to buy shares of Serba Dinamik Holdings Bhd . This means that the standard practice of the T+2 settlement cycle will not apply for the oil and gas services company for the time being.