Companies Act (Cap. 50): Primary legislation governing company formation, share issuance, shareholders' rights, share capital structure, transfer of shares, directors' duties and corporate governance requirements

Securities and Futures Act (Cap. 289): Regulates securities offerings and trading, including disclosure requirements and restrictions on share offerings

Income Tax Act: Governs tax implications of equity transfers, employee stock option schemes (ESOS) regulations, and capital gains considerations

Employment Act: Relevant for equity as part of employment compensation and regulations regarding employee share schemes

Competition Act: Addresses ownership structures and merger control provisions where applicable

Personal Data Protection Act: Outlines requirements for handling personal data of shareholders

MAS Guidelines: Monetary Authority of Singapore guidelines applicable if the startup involves regulated financial services

SGX Listing Rules: Singapore Exchange listing rules to consider if future IPO is contemplated

Company Constitution: Must ensure alignment with company's constitutional documents and existing governance structure

Shareholders' Agreement: Must ensure new equity agreement does not conflict with existing shareholders' agreements and covers key rights including vesting, transfer restrictions, pre-emptive rights, tag-along/drag-along rights, anti-dilution, exit rights, voting rights, and information rights