Today Marriott closed its purchase of Starwood Hotels & Resorts and introduced point convertibility between the Marriott Rewards and Starwood Preferred Guest programs. After linking your accounts, points are now transferrable between the two programs in either direction at a ratio of 3 Marriott Rewards points to 1 Starpoint.
Upon seeing this news, my first reaction was, "doesn't this make Marriott Flight and Hotel Packages astonishingly cheap?"
Well yes, yes it does.
Starwood's new 33%-46% transfer bonus
The math behind Marriott Rewards Flight and Hotel Packages normally works like this: if you book 7 Marriott Rewards nights at full price, you can transfer 50,000, 70,000, 100,000, or 120,000 points at a 1:1 ratio to a domestic airline (the ratio is different for many foreign carriers). If you choose United as your transfer airline, you receive a 10% bonus.
For example, 7 nights at a 25,000 Category 5 Marriott Rewards property would cost 150,000 points (since the 5th night is free). With a Flight and Hotel Package, you can instead spend 200,000, 220,000, 250,000, or 270,000 Marriott Rewards points and receive the difference in airline miles with Alaska, American, Delta, Air Canada, or British Airways, along with a few others.
Since Starpoints now transfer to Marriott Rewards at a 1:3 ratio, 270,000 Marriott Rewards points cost 90,000 Starpoints. 90,000 Starpoints, transferred directly to an airline partner, would yield 110,000 miles. Transferred first to Marriott Rewards, it yields 120,000 miles (132,000 United MileagePlus miles).
This is worth doing even if you don't plan to stay a single night with Marriott, as long as you have a use for the miles. If you are planning a 7-night stay somewhere anyway, then the value becomes virtually unbeatable.
This makes the Starwood Preferred Guest American Express card great for unbonused spend
As long as this option persists, manufacturing unbonused spend with the Starwood Preferred Guest American Express card will earn 1.33 to 1.46 miles per dollar spent with all the major US carriers, when Starpoints are transferred to Marriott Rewards in batches of 90,000.
While the Chase Freedom Unlimited earns a slightly higher 1.5 United MileagePlus mile or British Airways Avios, earning Starpoints instead gives you access to those currencies as well as Delta SkyMiles and American AAdvantage and Alaska Mileage Plan miles.
Obviously, the more of the 7 included Marriott hotel nights you use, the more value you'll get from this technique, but as shown above it's worth doing even if you don't use a single one of your included nights.
Note that you don't have to decide on a property and dates for your stay at the time of redemption — the award is deposited into your account, and can even be upgraded later if you decide to stay at a property in a category higher than the one you paid for.