IG Group's London mayoral election barometer shows that the Conservative candidate's chances stand at just 8.5 per cent, down from 12.5 per cent last month.
To be fair, since the start IG's clients have backed Labour's Sadiq Khan. But Goldsmith's chances have plummeted from 35 per cent back in February, with Khan's chances growing to now surpass the 90 per cent mark.
Khan's chances now stand at 91.5 per cent, according to the financial traders.
"Zac Goldsmith overcame the odds back in 2010 to win the constituency seat of Richmond Park but IG clients are predicting little chance of history repeating itself in next week’s Mayoral election," Matt Brief, head of dealing at IG Group, said.
"Our barometer has always indicated a more convincing win for Khan and our forward looking indicators previously correctly predicted Boris Johnson’s re-election victory in 2012."
Recent polling has also put Khan strongly ahead of Goldsmith, especially after second preferences are counted.
On key issues Khan is leading Goldsmith in perception. Both have pledged to improve the transport network, policing and tackle air quality. But in each of these areas Khan is thought of as more likely to deliver, according to the poll.