Lee Westwood has also moved out to 16/1 while Padraig Harrington and Rory McIlroy are 18/1 with Donald.
Coral will refund ante-post win bets if a selection is second to a British player.
“We’re looking to be highly competitive about all the leading contenders for the biggest golf tournament of the year, and as well as refunding stakes on any player finishing second to a British golfer, we will also lay any win bet to lose at least £10,000,” said Coral’s David Stevens.
**Open Championship Outright
9 Tiger Woods, 16 Lee Westwood, 18 Luke Donald, Padraig Harrington, Rory McIlroy, 33 Graeme McDowall, Justin Rose, Phil Mickelson, Rickie Fowler, 35 Sergio Garcia, 40
Adam Scott, Ernie Els, Francesco Molinari, Hunter Mahan, Ian Poulter, Louis Oosthuizen, Martin Kaymer, 50 Charl Schwartzel, Dustin Johnson, Jason Dufner, Jim Furyk, Paul Lawrie, Steve Stricker, 66 Nicolas Colsaerts, Ross Fisher, Peter Hanson, Matt Kuchar, Nick Watney, Bubba Watson, 80 Zach Johnson, 100 Ben Curtis, 125 Bar
25 Tiger Woods to win by one shot, 28 Tiger Woods to win by two shots, 40 Tiger Woods to win by three shots
45 Lee Westwood to win by one shot, 55 Lee Westwood to win by two shots, 80 Lee Westwood to win by three shots
55 Luke Donald to win by one shot, 60 Luke Donald to win by two shots, 90 Luke Donald to win by three