Taiwan's policy of economic rapprochement with political rival and erstwhile enemy China has led to a boom in mutual investment and business ties, but the financial services sector has lagged behind, in part due to the acute sensitivity in Taiwan over opening such a strategic sector. Bank of China and Bank of Communications, along with China Merchants Bank and China Construction Bank , are the only mainland banks in Taiwan, but they currently only have representative offices. Only seven Taiwan banks operate in China, but in niche areas including insurance and lending to Taiwan firms. The Financial Supervisory Commission, Taiwan's financial markets regulator, said in a statement late on Thursday that under the rules of a trade pact signed in 2010, the banks are allowed to upgrade after having offices open for one year. The two opened their offices in Taipei in September 2010.