Bookies say around 70% of all bets placed have been on the timber mosque, with odds currently 7:4.
The outsider is now Stanton Williams’ keyworker housing in north-west Cambridge, at 11:2.
Betting has not been brisk so far this year with William Hill taking “four figures not five” by Tuesday afternoon, though spokesman Rupert Adams said the last 24 hours were always the busiest so everything could change again.
Betting on the Stirling Prize is a niche interest, he added, meaning that all it takes is a couple of £50 bets to change the market disproportionately.
“Compare that to football, where it would take a £50,000 bet to change the market,” he added.
The jury, chaired by Norman Foster, will announce its decision at about 7.45pm on Thursday, at a ceremony held at Coventry Cathedral and broadcast live on BBC Radio 4’s Front Row arts programme.
>> Also read: Revealed: Stirling Prize shortlist announced
The odds for the 2021 Stirling Prize
7:4 – Cambridge Mosque by Marks Barfield
11:4 – Windermere Jetty Museum by Carmody Groarke
9:2 – Tintagel Castle footbridge by Ney & Partners and William Matthews Associates
5:1 joint – Kingston University Town House by Grafton Architects
5:1 joint – 15 Clerkenwell Close, London by Amin Taha’s Groupwork
11:2 – Keyworker housing, Eddington by Stanton Williams