The value of precious metals held by China’s biggest lenders surged 66 percent from a year ago as banks lease more gold to customers because tighter borrowing rules make it harder to lend funds.

Precious metals held by Industrial & Commercial Bank of China Ltd., China Construction Bank Corp., Agricultural Bank of China Ltd. and Bank of China Ltd., the country’s four biggest lenders, were worth 378 billion yuan ($62 billion - 1445 tonnes) at the end of the second quarter, according to financial reports.