China's largest banks capped a sixth year of record profits by posting a 21 percent average return on equity, more than twice the rate earned by US and European competitors led by JPMorgan Chase & Co, Industrial & Commercial Bank of China Ltd and its three major local rivals boosted their combined profits 15 percent to 716.2 billion yuan ($115 billion), filings over the past week show.

By comparison, earnings at the four largest US lenders rose 9.6 percent to $51.9 billion while their ROE, a measure of how well the firms invest shareholder funds, averaged about 7.3 percent, according to data compiled by Bloomberg.