Your points are bought by your bank, with the fees shops pay on your card, from airlines at roughly 1 to 1.5 cents a mile (an estimate). Amex paid Delta $8.2 billion in 2025. Airlines carry your miles as debt, borrowed about $26 billion against them in 2020–21, and raise award prices over time (+28% from 2019 to 2024). In Europe interchange is capped at 0.3%, so cards earn less. Price every redemption in cash before you spend points.
1 · The swipe
Every time you pay, someone buys a mile.
Pay $100 on a US premium rewards card and the shop pays your bank about $2.10 to $2.65 in interchange (2025). That money is what your points are made of.
The bank turns it into miles by buying them from airlines in bulk, at roughly 1 to 1.5 cents a mile. That price is never published; it's the industry's best estimate.
CardFellow (Visa interchange, 2025) · View from the Wing, 2023 · One Mile at a Time, 20252 · The cheques
Airlines sell more miles than seats.
In 2025 American Express paid Delta $8.2 billion, mostly for SkyMiles. Delta wants $10 billion. American took $6.2 billion from its card partners.
Before the pandemic, 71% of the cash United's MileagePlus brought in came from selling miles to partners, mostly Chase (2019). Flying is the product; miles are the margin.
Delta FY2025 10-K · American FY2025 10-K · United 8-K, 20203 · The spread
A point has three prices.
Amex's average cost per Membership Rewards point works out to about 0.68 cents (our estimate from its 2025 annual report). Banks pay airlines around 1 to 1.5 cents a mile. And you're told a point is worth 1.5 to 2 cents or more.
Everyone in the chain does well while those three numbers stay vague. The only number that counts for you is what this point buys on this trip, against the cash price.
American Express FY2025 10-K · View from the Wing, 20234 · The loan
Your miles are on the airline's balance sheet, as debt.
Unused miles are a liability: at the end of 2025 American owed members $10.6 billion of travel in miles, Delta $9.3 billion and United $7.8 billion. That's more than each owes for tickets already sold.
In 2020 and 2021 the three borrowed about $26 billion against their programs. Lenders valued United's MileagePlus at $21.9 billion, more than the airline itself was worth at the time.
American FY2025 10-K · Delta FY2025 10-K · United FY2025 10-K · United 8-K, 20205 · The creep
The price of "free" goes up.
Award prices don't fall. The cheapest US award tickets cost 28% more points in March 2024 than in March 2019, seven points above inflation. In 2024 the US Department of Transportation opened an inquiry into how the four biggest programs change their prices.
Dynamic pricing makes it quieter: no chart to compare, just a higher number. Flying Blue split its awards into Light, Standard and Flex fares in September 2026.
IdeaWorks via Business Insider · US DOT probe, 2024 (AirlineGeeks) · One Mile at a Time: Flying Blue, 20266 · Europe
Why your European card earns less.
The EU caps interchange on consumer credit cards at 0.3% (since 2015). A US premium card brings in seven to nine times as much, so European banks have far less to buy miles with. Amex fills some of the gap from its own merchant fees and annual fees.
You can see it in the transfer ratios. A US Amex moves to Flying Blue at 1:1; in Belgium and, since July 2026, the Netherlands it takes 2 points for 1 mile. Belgian Amex lost its Miles & More transfer in May 2025.
EU Regulation 2015/751 · CardFellow (Visa interchange, 2025) · Platinum Flyer: Amex NL to Flying Blue7 · You
So: points or cash?
Treat points like a currency that slowly loses value: earn them, then spend them on a trip where they beat the cash price, not on whatever is left.
That's what Mila does. Tell her the trip and the points you hold; she works out the cents per point for your card's country, against the real cash fare, and tells you which way to pay.
- The swipe
- The cheques
- The spread
- The loan
- The creep
- Europe
- You
Figures are from company filings and the sources linked under each chapter, with the year they apply to. Prices per mile and Amex's cost per point are estimates: no bank publishes them. Full research: what banks pay, airline accounting, transferable points and the European rules, dated and sourced. Information, not financial advice.