Shares of Hong Kong Exchanges and Clearing Ltd. (HKEX) slumped more than 11 percent after the global financial hub decided to increase the stamp duty for stock trading on Wednesday. 

The tax hike was officially announced by Paul Chan, the financial secretary of the Hong Kong Special Administrative Region (HKSAR) government after the morning session. 

"Having duly considered the impact on the securities market and our international competitiveness, we have decided to introduce a bill to raise the rate of stamp duty on stock transfers, from the current 0.1 percent to 0.13 percent of the consideration or value of each transaction payable by buyers and sellers respectively," Chan said. 

"Whilst we are disappointed about the government's decision to raise [the] stamp duty for stock transactions, we recognize that such a levy is an important source of government revenue," an exchange spokesperson said, according to Bloomberg. "HKEX looks forward to continue working closely with all its stakeholders to drive the continued success, resiliency, vibrancy and attractiveness of Hong Kong's capital markets."

The HKSAR government will continue to spare no efforts in introducing measures to facilitate the development of the securities market, so as to take the financial services sector to the next level, according to Chan.