Candidates have to achieve five per cent of first-preference votes to have the money returned.
In March, Mr Fox told the Standard that his campaign was being funded solely by the millionaire financier Jeremy Hosking, a former Tory donor who has also funded the Brexit party.
Other candidates set to lose their deposit include UKIP’s Peter Gammons, Piers Corbyn, YouTube prankster Niko Omilana and Count Binface.
Lib-Dem Luisa Porritt’s chances of saving her deposit are on a knife-edge.
By 2.45pm Ms Porritt was on four per cent but had votes still to come from traditionally stronger Lib-Dem areas such as South West and Merton and Sutton.
She was polling at 10 per cent in South West, and at five per cent in Merton and Wandsworth and in Croydon and Sutton.
Only Sadiq Khan, Shaun Bailey and Green candidate Sian Berry – who has consistently remained in third place overall – appeared sure to save their deposit.
The money – likely to total £160,000 or £170,000 – will be retained by London Elects and used to off-set the costs of running the elections.