Registering your company name with ACRA, the Accounting and Corporate Regulatory Authority (ACRA), is the mandatory requirement for starting a new business in Singapore while registering your domain name with SGNIC or any other domain registry is essential for reserving a .com.sg or .sg domain of your choice. However, neither of these will give you the rights of a registered trademark.
A trademark registration provides you with the exclusive rights to your brand. This is something the ACRA or SGNIC registration cannot do. In other words, if another company uses your company name or domain name as his trademark or the brand of his products or services, it will be almost impossible to stop him from using your branding without a trademark registration. This is especially so for smaller companies with new brands that do not have a strong reputation in the market.
If you intend to use your company name as the brand of your products and services, it will be a good idea to register it as a trademark with the relevant IP office.