His assets have yet to be divided up and his probate could take up to five years to sort as lawyers untangle assets locked into business and property abroad.
It is believed the star's wealth will be divided between wife Dwina and kids Melissa, Spencer and RJ, reported Sun Online.
Housekeeper Claire Yang, with whom Gibb, 62, had a child, is said to have received a USD 5 million settlement before his cancer death in May.
Land registry records show the 850,000 pound house he bought her in his home town of Thame, Oxfordshire, was put in her name.
Gibb's property portfolio includes his 15 million pound family home, a 2.6 million pound Miami Beach mansion and 8 million pound mews house in South Kensington.