Marriott is awarding 5000 bonus points for every three stays paid for with an American Express card between September 15th and January 31st.

Registration is required, and the bonus can be earned up to five times.

It’s always interesting to see promotions like this one with hotels and airlines that otherwise don’t partner with the credit card issuer. Marriott teams with BankOne to offer a co-branded Visa, and is has split with the American Express Membership Rewards program. Yet they managed to come to terms with Amex to fund this promotion.