China has made an initiative to start an Asian Regional Development Bank. This Bank would be aimed at providing funds to infrastructure projects and the region. This bank would be led by a Chinese official in Beijing and would begin with a fund in the range of 50-100 billion dollars.
The United States has opposed the creation of this bank. They see it as an opposition to the World Bank and the International Monetary Fund. These funds were set up with the United States at the head and the U.S. does not wish to lose control. Beijing counters these claims by saying that this new bank would work in concert with these funds. They also say that it is important for the expanding infrastructure to create a new fund in the region.
Despite U.S. urgings to stay out of the bank, 40 countries have signed up as founding members including U.S allies such as France and Germany. Australia was the latest to join, saying that they did not wish to be left out of Chinese plans in the region. The bank plans to begin by the end of the year.
Source: http://www.nytimes.com/2015/03/29/world/asia/australia-to-join-regional-development-bank-led-by-china.html?ref=topics&_r=0
See comments on multiple previous posts on AIIB.