American Express is running a 35% transfer bonus to Marriott Bonvoy through December 10, 2026. That turns the usual 1:1 ratio into an effective 1,000 Membership Rewards points for 1,350 Bonvoy points. It's live, it's straightforward, and transfers are instant.

Sounds like free money until you run the numbers. Bonvoy points are currently valued around 0.73–0.8 cents apiece by most analysts after this year's quiet devaluation that hit high-end properties hardest. Even with the bonus, you're looking at roughly 1.0 cent per transferred Amex point on average redemptions. That's not terrible, but it's not the 1.5–2.0 cents your Amex points routinely deliver elsewhere.

The Redemption Math That Actually Matters

Let's get specific. At dynamic pricing properties, a Category 7–8 equivalent like a standard St. Regis or Ritz-Carlton often runs 60,000–85,000 points on off-peak or shoulder dates, climbing to 100,000–140,000+ during peak demand. Top Maldives villas or Reserve properties? Expect 120,000–220,000 points per night when cash is $2,000–$3,000.

With the bonus, 100,000 Amex points get you 135,000 Bonvoy. That covers a 120,000-point Maldives night with some left over. If that room costs $2,200 cash, you're looking at about 1.83 cents per Bonvoy point — or roughly 2.47 cents per original Amex point. That's a win.

Contrast that with a $600 urban Ritz night costing 70,000 points. Same math yields about 0.86 cents per Bonvoy point. You're destroying value. The 35% bonus doesn't magically fix mediocre redemptions; it just makes the good ones slightly better.

Marriott's fifth-night-free on award stays helps, effectively dropping a five-night Maldives trip from ~600,000–800,000 points to 480,000–640,000. That's real leverage if your dates align. But resort fees, seaplane transfers, and meal plans remain cash. Always run the total cost.

How It Stacks Up Against Other Amex Partners

Transfer the same 100,000 Amex points to British Airways Avios or Iberia Avios (1:1, occasional bonuses) and you can access short-haul business class or position for long-haul sweet spots. Virgin Atlantic Flying Club often prices ANA first class or Delta One to Europe at rates that crush hotel value on a per-point basis.

Avios programs give you outsized returns on short European hops or transatlantic premium cabins when fuel surcharges aren't brutal. Virgin's dynamic but partner-friendly pricing frequently delivers 2–4 cents per point on aspirational redemptions. Those currencies don't have the same "feels like paying cash anyway" tax and fee creep that Bonvoy sometimes delivers.

The math is clear: Amex points retain more optionality with airline partners. Marriott is the hotel of last resort for your MR balance, not the default.

When the Bonus Actually Moves the Needle

This promotion wins in three narrow cases. First, you're already staring at a specific high-cash-rate aspirational booking — think St. Regis Vommuli overwater villa in peak season or Ritz-Carlton Reserve in Costa Rica or Bali where the points price lags the rack rate significantly. Second, you need a small top-off for an existing Bonvoy balance before the window closes. Third, you're combining with a 5th-night-free stay at a property where the effective nightly cash equivalent exceeds 1.8 cents per point after all taxes and fees.

Everywhere else — city hotels, shoulder-season U.S. resorts, standard Category 5–6 properties — the transfer is a value leak. Bonvoy's dynamic pricing has a habit of matching or exceeding cash rates at exactly the properties where points collectors want to stay. Don't convince yourself otherwise because a shiny 35% bonus is waving at you.

The clock is ticking until December 10. Points transferred are gone forever. Check availability first, calculate the true cents-per-point on your exact dates including all ancillary costs, and compare against paying cash while earning Bonvoy points naturally or using an alternative Amex transfer.

Action item: Pull up your target dates at 2–3 specific aspirational properties right now. If the redemption clears 1.7+ cents per Bonvoy point after the bonus, transfer only what you need and book immediately. Otherwise, leave those Membership Rewards points where they are. The next Marriott bonus will be along soon enough, and your Amex points will still be waiting.