Mexican fast food chain Guzman y Gomez was dealt its first setback since staking its claim as 2024’s best-performing float after its American outlets suffered a fall in sales and cast doubt over co-founder Steven Marks’ aim to crack the world’s biggest market.

Guzman y Gomez, known for its breakfast burritos and $12 chicken meals, is on track to easily beat its prospectus profit forecast this year after posting strong sales and earnings growth in the first half.