A gift letter is a piece of legal, written correspondence explicitly stating that money received isn't expected to be repaid. The IRS taxes gifts made over a certain dollar amount.The general rule is that any gift is a taxable gift. However, there are many exceptions to this rule. What Are The Tax Implications of a Gift Letter? Let's look at the tax implications of receiving a gift for your down payment and how you can minimize your risk. Gift Letters And Taxes. Such a gift is deductible up to 30 percent of a donor's adjusted gross income. Any excess can be carried over for five additional years. You should make sure the gifter understands the tax implications of gift funds if you want to avoid family problems.