Update: Since this post was published, Finland has also announced it is applying to join.

Russia, the Netherlands, and Australia announced over the weekend that they will be joining the Chinese-led Asian Infrastructure Investment Bank (AIIB), whose membership has become something of a test of diplomatic clout between China and the United States. The development bank is seen as a challenger to existing institutions like the World Bank or the Asian Development Bank.

Unable to increase its voice in the current institutions—China commands just 6.47% of the vote in the Asian Development Bank, 5.17% in the World Bank, and 3.81% in the International Monetary Fund—China is building its own alternative. The bank is intended to make up for the gap in funding the region needs—about $800 billion a year in infrastructure investment, according to the Asian Development Bank. It is expected to launch later this year.

So far, just over 40 countries have joined AIIB, with one day left before the deadline to join as a founding member expires. The United States and only one of its main allies, Japan, remain absent from that list. The US and other critics question whether the Beijing-led institution will uphold international standards of transparency, debt sustainability, and environmental and social protections, or just turn into an arm of Chinese foreign policy. Last week, Japan’s finance minister said, “Unless [China] clarifies these matters, which are not clear at all, Japan remains cautious.”

But as more countries join the bank, the more likely AIIB will have to follow international standards, observers have noted, and the less likely China will be able to use a multilateral institution to wield influence in the region. Here are all the countries that have joined or applied to join the AIIB aside from Spain, which said late last week that it would also apply to be a member (link in Spanish), and South Korea.