The mum of four is tipped to file for divorce in days.
Hollywood action hero Schwarzenegger, 63, has a vast property portfolio including an entire shopping mall, plus shares in Coca-Cola and Starbucks - and an 8million pound LA home.
'The Terminator' star's wealth has been estimated at 310million pounds and Shriver , 55, could be entitled to half.
It would dwarf the 100million pounds basketball star Michael Jordan paid ex Juanita Vanoy in 2007 - the current celebrity record. And it is more than twice the 65million pounds Tiger Woods is said to have given Elin Nordegren in their split.
Maria has hired a private eye to probe Schwarzenegger's finances.
"She'll get every last penny she is entitled to," the Sun quoted a source as saying.
"Arnold is an extremely rich man - no one is quite sure how rich but Maria's team will find out. He seems to have invested wisely and could be worth 500million dollars," the source added.
The couple split after 25 years when Schwarzenegger admitted fathering a boy, now 13, with a housekeeper.
