NEW YORK (AP) — American Express will become the exclusive credit card issuer for Hilton Hotels, the company said Thursday, a major success for a business that has been facing increased competition.

The New York-based credit card company will be the sole issuer of the Hilton co-branded credit card starting Jan. 1, 2018. Currently Hilton has credit cards issued by Citigroup and AmEx.

Hilton Hotels is one of American Express’ oldest relationships. Hilton started taking American Express cards in the late 1960s and the two companies issued its first co-branded credit card in 1995. In 2000, Hilton added Citi as an issuer, and the two banks have been issuing Hilton-branded cards simultaneously since then.

Co-branded credit cards are those for which a major retail or travel company teams up with a bank to issue the cards, typically aimed at increasing customer loyalty. Most major retail or travel companies have some sort of co-branded card nowadays, which earn reward points or cash back for their use. It’s a lucrative business for companies like American Express, who has co-branded cards with Hilton, Delta Air Lines, Starwood Hotels and Mercedes-Benz.

But American Express has seen increased competition for co-branded credit card partnerships, losing its exclusive arrangement with Costco to Citigroup last year, as well as its JetBlue co-branded card. It’s also not clear whether AmEx will be able to hold onto Starwood, which it was purchased by Marriott who has its own co-brand card with JPMorgan Chase. When Hilton announced last year that it wanted to move to a sole issuer of its credit card, it was expected AmEx would want to hold onto Hilton after losing the other partnerships.

Along with its co-branded cards, AmEx has faced more competition in other markets. The American Express Platinum Card, which gives points plus airport lounge access and other benefits, saw its first major competitor from Chase, when the bank created the Chase Sapphire Reserve Card, which became so popular the bank initially ran out of the metal it was using to make it.

How losing Hilton will impact Citi remains to be seen, but the impact is likely to be minor. A Citi spokeswoman said its Hilton co-brand cards represented roughly 1 percent of Citi’s overall card loans.

“Citi and Hilton enjoyed a terrific co-brand credit card partnership however during negotiations, it became clear that terms of exclusivity given the relatively small size of the portfolio were not economically viable,” said Jud Linville, CEO of Citi Global Cards, in a statement.

American Express shares were up more than 1 percent in afternoon trading.