The Princess – the daughter of His Majesty the King and HRH Princess Soamsawali – is being treated at the hospital for a heart-related ailment.
Marut was accompanied by Adisak Limparungpatanakij, a special advisor to Nation Group and Aeumsree Boonhachairat, an advisor to its chief executive officer.
The Nation Group executives offered a vase of flowers before a portrait of the Princess and wrote messages conveying their wishes for a quick and full recovery.
Staff at Nation Group are worried about her condition and hope she will recover soon, Marut said, adding that the company plans to hold a religious ceremony for her.
The Royal Household Bureau said in a statement on Thursday that the Princess had fainted while training her dog for a contest in Nakhon Ratchasima province on Wednesday evening. She was subsequently hospitalised.