Average profit margins of companies have increased by almost a third compared with before the pandemic, a study of thousands of firms suggests.

Unite said its research into the profits of almost 17,000 UK companies showed a continuation of the country’s “corporate profiteering crisis”.

Some of the biggest increases have been in big banks, oil and gas, electricity generation, supermarkets, and shipping companies, said the union.

Unite general secretary Sharon Graham said: “Over the last two years, Unite has consistently called out the profiteers driving the cost-of-living crisis.

“While workers have been hit with the biggest fall in real wages and living standards in generations, corporations have racked up hundreds of billions in profits.

“Now our latest report, examining 17,000 companies, shows this profiteering crisis is far from over.

“This is why our economy is broken – because of the choices of executives, investors and politicians who choose short-term profits and fat dividends over investing in our industries and public goods.”

Unite said its study indicated that thousands of companies of all sizes have boosted their profits during the cost-of-living crisis, while wages have “stagnated”.

Unite said its study was the largest of corporate profits since the pandemic and found that average profit margins have increased by 30% compared with the pre-pandemic period.