There is no maximum amount. They can send you 17 trillion dollars if they have it to give you. However, any amount over $10,000 will automatically be reported to the treasury department by the financial institution in the U.S. that receives it. The Treasury Dept has nothing to do with the IRS. There is no requirement for the recipient of a gift to report it to anyone at any time for any reason. The giver of any gift over $14K in any one tax year is the one required to report it to the IRS. There's no tax assessed provided the gift is under $5.2M.
