(File photo)

The Asian Infrastructure Investment Bank (AIIB) was formally established on Friday after it garnered enough countries' domestic approval.

The launch of the bank, the first major multilateral lender with developing countries holding the majority of the shares and votes, came just six months after an articles of agreement (AOA) was signed by 57 prospective founding members in June, and 26 months after President Xi Jinping proposed it in October 2013.

According to the AOA, the bank can be legally valid as long as more than 10 countries, with their represented total subscribed capital no less than 50 percent of the total capital, get the AOA approved by their legislatures.

So far, 17 countries have approved the mini-constitution and submitted to Beijing. Their combined subscribed capital makes up 50.1 percent of the total, according to a statement by China's Ministry of Finance.

The 17 countries are: Myanmar, Singapore, Brunei, Australia, China, Mongolia, Austria, the United Kingdom, New Zealand, Luxemburg, South Korea, Georgia, the Netherland, Germany, Norway, Pakistan, and Jordan.

The bank will be operational in mid-January, and the bank's Board of Governors and Board of Directors will hold their first meeting from Jan 16 to 18 in Beijing. More prospective founding members will approve the AOA and deliver to Beijing between the time window.