China's banking regulator has fined 12 banks over illegal trading of 7.9 billion yuan of bank bills -- that's about 1.25 billion US dollars. The China Banking Regulatory Commission said on Saturday that the violations had severally disrupted market order, and showed the institutions were lacking internal controls and had poor compliance. The CBRC investigated a branch of the Postal Savings Bank of China in Gansu province, and uncovered the case. The banking watchdog also said it will step up the efforts to clamp down on market chaos in the banking sector, and will investigate other major fraud cases.