It calculates that cancelling bank holidays would boost the output of the economy by £19bn a year.
Spreading them throughout the year would help industry by stopping businesses “losing momentum,” it argues.
The extra bank holiday for the Queen’s Diamond Jubilee this year means there are five in April, May and June in England and Wales. In Scotland, Easter Monday is not a holiday.
In total, England and Wales normally have eight bank holidays, while Scotland has nine and Northern Ireland has 10.
Douglas McWilliams, CEBR founder, told the BBC’sBreakfastprogramme: “About 45% of the economy suffers; the offices, the factories, the building sites where people tend not to go to work on bank holiday.”
But Paul Kenny, GMB union leader, slammed the report as "utter rubbish".
Unions have long called for more public holidays, pointing out that other European countries have more than the UK's minimum of eight.
Spain has a statutory minimum of 13 bank holidays, Portugal has 13, Greece has 12, France has 11, while Germany and Ireland both have nine.