“Spieth proved he is the man of the moment with back to back major victories and could dominate the game for years to come,” the bookmakers said in a news release on Monday.
“William Hill now offer just 20-1 that he manages to win the grand slam in 2015 while he is 7-1 to win the Open at St Andrews.”
Rory McIlroy is the 7-2 favourite to land the coveted Claret Jug for the second year running.
Spieth's meteoric rise has propelled the 21-year-old within 1.71 points of McIlroy at the top of the world rankings, a list the Northern Irishman has topped since August.
Looking further ahead Hill's are offering odds of 20-1 on Spieth equalling or exceeding Jack Nicklaus' record of 18 major wins.
The British Open, golf's oldest major, starts on July 16. – Reuters
Original source: Spieth tipped for more major succcess