Bank of America pays female staff in Britain 28.7% less on average than male employees, according to a report released Tuesday.
The divide widens to 57.9% for year-end discretionary bonuses. The newly required disclosures compare the total earned by all male U.K. staff with the total for the female staff.
The gap reflects the high concentration of men in more lucrative senior positions; a bigger share of lower-paid jobs are held by women.
The disparity in pay at the U.S. bank's British unit is narrower than at HSBC, where women were paid an average 59% less than male employees. Goldman Sachs reported a gender pay gap of 56% for its employees.
The national average pay gap is about 18%, according to the Office for National Statistics.
"We are committed to bringing more women into financial services at a senior level, and into roles that offer the prospect of significant progression," Bank of America said in the report.