MADRID (Reuters) - The board of Spanish infrastructure firm Abertis will meet on Monday to discuss moving its head office out of Catalonia as the region s parliament considers unilaterally declaring independence from Spain, a source familiar with the matter said. Several big Catalan companies have announced plans to move their registered office to other cities in Spain after Catalonia went ahead with an independence referendum last week which was banned by a Spanish court. There was no immediate comment from Abertis, which builds, maintains and operates highways in Spain, France and the Americas. Italy s Atlantia bid 16.3 billion euros ($19 billion) for Abertis in May to create the world s biggest toll road operator. ($1 = 0.8523 euros) 