The Payment of Bonus Act 1965 provides rules for bonus payments to employees in India. Key points: - It applies to factories and establishments with 20+ employees. Bonus is calculated based on allocable surplus which is a percentage of available surplus. - Eligible employees must work at least 30 days in a year. Minimum bonus is 8.33% of wages or 100 rupees, whichever is higher. - Maximum bonus is 20% of wages if allocable surplus exceeds minimum bonus amount. Surplus can be carried forward for 4 years for bonus payments.