BOGOTA, July 18 (Reuters) - Grupo Carrefour Brasil SA's initial public offering could price at the bottom of a suggested price range later on Tuesday, reflecting concern over too stretched a valuation for Brazil's biggest supermarket chain, three people familiar with the matter said.

Late on Monday night, investors had placed less than twice the size of Carrefour Brasil shares on offer at the IPO, based on a price of 15 reais a piece, said the people, who requested anonymity to discuss the deal freely. The company and shareholders expected to raise up to 5.6 billion reais if the IPO were price at the ceiling of the range, or 19 reais per share. (Reporting by Guillermo Parra-Bernal; Additional reporting by Dominique Vidalon)