According to AIIB website, the project aims to mobilize private capital for infrastructure and other productive sectors by investing in non-controlling equity stakes in companies in AIIB members via a fund.
ACCOUNTABILITY MECHANISM OF AIIB
In addition, the AIIB has a Bank Oversight Mechanism. According to AIIB's policies, "people who believe they have been or are likely to be adversely affected by a failure of the Bank to implement the ESP may also submit complaints to the Bank's oversight mechanism in accordance with the policies and procedures to be established by the Bank for such mechanism." However, at the time of writing, it is unclear what the exact scope and function of this Oversight Mechanism will be.