A BUSINESSMAN was robbed of $4.65 million in cash by four helmeted motorcyclists as he walked out from a bank in Tsim Sha Tsui yesterday. The gang punched Ma Tang-hung, 42, snatched his briefcase and sped away on two motorcycles. Mr Ma managed to note the number plates of the motorcycles and gave them to the police, who found that one of them had been reported stolen from Kwun Tong that day. Mr Ma told Yau Tsim detectives he took US$600,000 to the Po Sang Bank in Kimberley Road at 10 am to have it converted into Hong Kong dollars. Because of the huge amount involved, bank officials told him to return at 1 pm to make the collection. When he returned, officials gave him HK$4.65 million and he put it in a case. He said that as he walked out of the bank he noticed four men wearing helmets sitting on the motorcycles. The men approached him and two began to punch him while one of them grabbed his briefcase.