In 2026, transferring American Express Membership Rewards points to Delta SkyMiles is not entirely free for U.S. cardholders due to a federal excise tax offset fee. American Express charges $0.0006 per point transferred, with a maximum cap of $99 per transaction. For example, if you transfer 50,000 points to Delta, you will be charged $30. This fee is unique to U.S. domestic airlines (like Delta, JetBlue, and Hawaiian) and does not apply when transferring to international partners like Air France-KLM or Virgin Atlantic—even if you use those points to book a Delta-operated flight. You have the option to pay this fee in cash (added to your monthly statement) or use Membership Rewards points to cover the cost, though using points is generally considered poor value (valuing them at only about 0.5 cents each). It is important to note that once the transfer is initiated, it is irreversible, so always confirm that your desired "Award Seat" is actually available on Delta's website before paying the fee.