Tax resident and non-resident companies are generally taxed in the same manner in Singapore. However, some clients need the certificate of SG tax residency for Double Taxation relief purpose, or letter of tax residency for other purpose (banks, tax incentives, etc)
Certificate/Letter of tax residency - we will need to apply to IRAS specifically to proof that the SG company owed by foreigner is a Singapore tax resident and the letter is getting more difficult to get. Having one board of directors' physical meeting in S'pore is not enough to proof the tax residency. IRAS requires a key person, e.g. ceo, coo, cfo, exective director︀ to be based in Singapore; or the SG company is supported administratively by other related︁ companies that have Sg business activities, to issue the tax residency letter for the company.︂