The story
It was founded in 1973 by the Finance Ministers at the first Organisation of the Islamic Conference (now called the Organisation of Islamic Cooperation) with the support of the King of Saudi Arabia at the time (Faisal), and began its activities on 3 April 1975.Ahmed Mohammed Ali Al-Madani was installed as the inaugural president and served until 2015.
On 22 May 2013, IsDB tripled its authorized capital to $150 billion to better serve Muslims in member and non-member countries. The Bank has received credit ratings of AAA from Standard & Poor's, Moody's, and Fitch. Saudi Arabia holds about one quarter of the bank's paid up capital. The IDB is an observer at the United Nations General Assembly.
From Wikipedia’s article on Islamic Development Bank, shared under CC BY-SA 4.0.5