Chief executives of the 100 largest companies in the UK will have earned the yearly wage of the average Monmouthshire resident by 1pm on Thursday January 4, figures suggest.
Analysis from the High Pay Centre shows pay for FTSE 100 CEOs currently stands at £3.8 million per year.
Meanwhile, separate Office for National Statistics figures show the median full-time wage for a worker in Monmouthshire in the 2022-23 tax year was £35,589.
It means a FTSE 100 CEO would need around 30 hours to surpass the average Monmouthshire full-time worker's annual wage.
Harvard Business School research suggests FTSE 100 CEOs work 12.5 hours per day.
Assuming they start work at 8 am, they will have earned the average yearly wage by 1pm on Thursday January 4.
The Trades Union Congress accused the Conservatives of "presiding over and enabling obscene levels of pay inequality".
General secretary Paul Nowak said: "While working people have been forced to suffer the longest wage squeeze in modern history, city bosses have been allowed to pocket bumper rises and bankers have been given unlimited bonuses.
"It doesn’t have to be this way. We need an economy that rewards work – not just wealth."
Mr Nowak said workers should be placed on company boards, called for wealth to be taxed more fairly, and urged the Government to "work with unions and employers to drive up living standards for all".
"Under the Tories, it is one rule for the super-wealthy and one rule for everybody else," he added.
The figures also show FTSE CEO pay increased by 9.5% in the last year, while across the UK, full-time average wages rose by 6%.
Luke Hildyard, the director of the High Pay Centre, said: "Lobbyists for big business and the financial services industry spent much of 2023 arguing that top earners in Britain aren’t paid enough and that we are too concerned with gaps between the super-rich and everybody else.
"They think that economic success is created by a tiny number of people at the top and that everybody else has very little to contribute.
"When politicians listen to these misguided views, it’s unsurprising that we end up with massive inequality, and stagnating living standards for the majority of the population."
A government spokesperson said: "We have given millions of workers across the UK a historic pay rise thanks to our decision to increase the National Living Wage to £11.44 an hour.
"In total since 2010, the annual earnings of a full-time worker on the National Living Wage will have increased by over £10,000, demonstrating how we are delivering for those in work."