Industrial & Commercial Bank of China Ltd and Bank of China Ltd won approval to change how capital ratios are calculated, in line with international standards, as regulators seek to ease financing constraints for the country's biggest banks.

ICBC, the nation's largest lender, and Bank of China, the fourth biggest, will be among the first in China to comply with Basel III guidelines for global banks' liquidity and risk buffers, they said in separate statements.

The new system may bolster banks' capital ratios by reducing the risk-weighting of some assets, analysts at China International Capital Corp wrote in a note on Thursday.