As a native:
No, Singaporeans do not require a visa to establish a business.

As a visitor:
If you are a foreigner who wishes to relocate to Singapore to run your business, you must first obtain the appropriate work visa or pass, such as the Employment Pass (EP), Dependant Pass with Letter of Consent (LOC), ONE Pass, EntrePass, or Personalised Employment Pass (PEP). The type of pass required will be determined by your credentials, work experience, and the nature of your business.