One of the biggest banks on Wall Street on Thursday unveiled an eye-popping pay gap.

Barclays, run by chief executive Jes Staley, pays its female investment bankers about half what it pays men in the same unit — underscoring the lack of women in senior positions.

On average, Barclays female investment bankers make 48 percent what their male counterparts do, the company said in its annual report Thursday.

UK banks, under a new law, are required to disclose pay disparity.

The report also shows that there’s a shrinking number of women in top roles, including managing directors and board members, since last year.

Staley, in the report, said he was “confident” that men and women got paid equally for the same job but that the bank has to continue to push to get more women into higher-level jobs.

Staley said it was the bank’s goal to increase female representation on Barclays’ board from 21 percent today to 33 percent by 2020.

Fifty-eight percent of associates, the lowest-level bankers, are women, while assistant vice presidents, one step up, are only 38 percent women, the bank said.

Managing directors, the highest level, are just 15 percent female.

US banks, like JPMorgan Chase and Goldman Sachs, have yet to report their data on pay. They have until April to make the disclosures.

Bank of America, Citigroup and Wells Fargo have all reported that they pay women 99 cents for every dollar they pay men. However, the banks haven’t released their methodology and skeptics have questioned those proportions.