By Adam Jusko,,

American Express and Delta Airlines announced a renewal of their long-running credit card partnership this morning, but somewhat buried in that announcement is the fact that the partnership is getting way more expensive for Amex.

The new agreement extends the partnership through 2029, but definitely not at the same costs to American Express. From the press release:

“As the two companies work together, Delta expects its benefit from the relationship to double to nearly $7 billion annually by 2023, up from $3.4 billion in 2018, strengthening Delta’s increasingly diversified revenue stream.

“American Express expects attractive growth economics over the term of the agreement and affirmed its previous guidance for 2019 of FX-adjusted revenue growth in the 8-10 percent range and adjusted earnings per share between $7.85 and $8.35, subject to any contingencies and legal settlements1. The economics of the new terms are not expected to have a material effect on the first quarter results of American Express.”

Reading between the lines, it appears that in four years American Express will be paying more than double the money it now pays Delta for the privilege of dishing out Delta miles and airport lounge access to its SkyMiles credit card holders. And when American Express talks about “attractive growth economics,” you might want to interpret that as “We hope this works out because we may have totally overpaid.”

American Express already lost Costco’s credit card business and losing Delta’s would have been catastrophic, at least from a public relations standpoint. Delta seems to have taken full advantage, negotiating a huge increase in revenue from the partnership. Delta’s shareholders are sure to be happy, while American Express shareholders may be less so.