THE ANTILA www . hba . com The Antila is a private home located in Mumbai , India . Express places its construction cost at approximately $ 2.14bn . First Post calls the real estate prices in Mumbai “ steady ”, citing the costs and complications of the 60 building approvals necessary to begin construction in the area . Express names the Antila the world ’ s most expensive private home , while Business Insider calls it “ the first billion-dollar home .” With 27 floors , and 400,000 sq ft of space , it took four years to build . Residing in the Antila are Nita Ambani , Mukesh Ambani and their three children . Forbes names Mukesh Ambani the fifth richest man in the world , placing his net worth at $ 43bn . They consulted with two architecture firms in order to design and build their custom home : Hirsch Bedner Associates , and Perkins + Will .