McDonald’s will offer Krispy Kreme doughnuts across the United States by the end of 2026, after a “successful test” at more than 160 of its restaurants in Kentucky and Indiana, the two companies said.

The announcement propelled Krispy Kreme stocks upward by almost 40 percent from the previous day to $17.35 per share by end of trading Tuesday. That marked the highest share price since January 2022. McDonald’s shares stayed flat at around $278 per share.

The partnership adds to a list of fast-food chains teaming up with snack makers. Wendy’s and Cinnabon introduced a new dessert in February, while Subway partnered with Cinnabon and Auntie Anne’s to add new snacks to its menu in January.

The move will more than double the locations at which fresh Krispy Kreme doughnuts or cookies can be purchased, the company said in a news release. A phased rollout will begin in the second half of this year, expanding to participating McDonald’s locations nationwide by 2026.

McDonald’s has about 13,500 U.S. locations, 95 percent of them operated by independent owners. Krispy Kreme chief executive Josh Charlesworth told investors last month that the company could serve 6,000 McDonald’s restaurants with its existing supply chain network. In sharing news of the collaboration, Krispy Kreme said it will seek to build up that infrastructure.

Krispy Kreme’s Original Glazed, Chocolate Iced with Sprinkles and Chocolate Iced Kreme Filled doughnuts will be delivered to McDonald’s locations daily, according to Krispy Kreme. Doughnuts will be available all day, sold individually or in a box of six, according to Guillaume Huin, a senior marketing director at McDonald’s.

“I 100% plan to make Krispy Kreme Doughnut x McDonald’s shake combo a thing,” Huin said on social media.

Krispy Kreme and McDonald’s launched a limited partnership in October 2022 to run a “small-scale test” to sell Krispy Kreme doughnuts at more than 160 McDonald’s locations in the Louisville and Lexington, Ky., areas. The locations will continue to serve Krispy Kreme doughnuts. Krispy Kreme has also been conducting a similar test run with Costco in international markets, the company told investors last year.