BEIJING, Oct. 28 (Xinhua) - Chinese banks held 257.3 trillion yuan (about 37 trillion US dollars) in onshore assets by the end of September, official data shows.

The volume expanded 7 percent year on year, according to the China Banking and Insurance Regulatory Commission.

Lenders' onshore liabilities rose 6.7 percent to 236.4 trillion yuan by the end of September, said the regulator.

The combined onshore assets of China's "big five" lenders -- the Industrial and Commercial Bank of China, Agricultural Bank of China, Bank of China, China Construction Bank and Bank of Communications -- came in at 92.5 trillion yuan, 36 percent of total assets in the industry.

China's city-based commercial banks recorded 33 trillion yuan in total onshore assets by the end of September, up 8.4 percent year on year, accounting for 12.9 percent of the industry's total.