Pret A Manger is reported to be close to agreeing a deal to purchase grab-and-go chain Eat.
The Financial Times has said the sandwich giant would look to convert Eat's 94 sites into vegetarian outlets.
A spokesperson for Pret A Manger said: "We never comment on rumour or speculation."
Eat was reported to be searching for a buyer earlier this year when private equity firm Horizon Capital, previously Lyceum Capital, appointed financial planner Spayne Lindsay to explore options.
Both Horizon and Eat declined to comment on the reports.
In February 2018 the sandwich chain said it was "considering various options regarding its business". It went on to announce the closure of 10% of its sites as it focused on the London market.
Niall and Faith MacArthur launched Eat in 1996. Private equity company Lyceum Capital bought the company from Penta Capital in March 2011.