Dear friend,
Eventhough the U.S Company is 'the parent company' and its Indian counter- part a 'subsiadiary company' or under whatever classification it falls, both are two distinct and separate entities for all practical purposes including personnel matters and only bound by the laws of the respective countries.As per the law relating to gratuity in India, as long as the employee is on the rolls of the company, his services with the company, not withstanding any occasional and temporary break necessitated by the employer like the one you mentioned, continues.Simply put, this kind of temporary lending of the services of employees between the two companies is "deputation' which retains the lien of the deputed employee with the deputing company. Therefore, it is for your U.S parent and Indian counter-part to have specific clauses relating to proportionate contributions to terminal benefits for the entire period of deputation in the agreement between the companies.Else, in case of termination of employment due to the reasons mentioned in the Payment of Gratuity Act,1972 during the course of deputation abroad or afterwards, you will be responsible to pay gratuity.So, my suggestion is to have allocation for annual contribution for usual terminal benefits and get it reimbursed from the U.S Company on pro-rata basis for the entire period of deputation. My above response is not with reference to the US Visa regulations about which I have no knowlege. Hence it is better to have the opinion of an Employment Consultant.