The Payment of Bonus Act, 1965 requires employers in India to pay annual bonus to eligible employees based on profits. It applies to factories and other establishments with 20 or more employees. The minimum bonus is 8.33% of salary or Rs. 100, whichever is higher. The maximum bonus is 20% of salary. Employers must calculate bonus using a specified formula and maintain registers showing computations. The Act establishes rights for employees to claim unpaid bonus and resolve disputes, and penalties for employers who violate the Act.