Republican presidential candidate Mitt Romney paid about $3m in federal income taxes in 2010.
Mr Romney’s tax returns show most of his $21.7m income came from his investments.
He also gave nearly $3m in total to charitable causes and the Mormon Church, helping to reduce his effective tax rate to about 14 per cent.
The former Massachusetts governor has been under pressure in recent weeks to release his tax returns.
Newt Gingrich, his rival in the race to win the Republican nomination for the United States presidency, made public his returns on Saturday, showing he paid almost $1m in income taxes.
Mr Romney’s taxes were reported yesterday in The Wall Street Journal and The Washington Post.
Mr Gingrich and Mr Romney clashed repeatedly in heated personal terms in a two-hour debate.
Mr Romney branded his chief rival as an “influence peddler” in Washington, only to be accused in turn by Mr Gingrich, the former Speaker of the House of Representatives, of spreading falsehoods over many years.
Mr Gingrich has seized the nomination momentum with a solid victory over Mr Romney in South Carolina but Mr Romney remains the favourite of much of the Republican establishment and has a big advantage in money and organisation.