[3][4] Initially made up of all Warsaw Pact members led by the Soviet Union alongside Cuba, Mongolia and Vietnam under the Eastern Bloc during the Cold War, IIB's membership was largely maintained until that point.

[7][8][9][10][a] Shortly following the dissolution of the Soviet Union, IIB stopped operating, and its obligations to its COMECON creditors were only addressed in 2001 by the Russian Ministry of Finance.

[15][16] Viktor Orbán gave IIB as well as "guests, business partners, experts" EU residence and full diplomatic immunity.

[17] In 2020, the IIB acquired the historic Lánchíd Palace [hu] on a prominent location adjacent to Budapest's iconic Széchenyi Chain Bridge for its head office.

[citation needed] The Board of Governors is the Bank's supreme collective governing body, consisting of representatives from the IIB's member states.

[31] The Bank's activities are controlled by the Audit committee, which is made up of representatives from the IIB's member states appointed by the Board of Governors.

With the relocation of IIB's headquarters to EU member Hungary, critics raised that the bank serves as a "Trojan horse"[37] for Russian intelligence operations and spy activities against the European Union.

[38] This claim is supported by the fact that the bank's former chief Nikolai Kosov has close ties with Russian intelligence agencies, and that his father was a KGB top operative in Budapest in the 1970s, while his mother was described as “one of the most extraordinary spies of the 20th century”.

[43] In October 2023 the bank failed to repay two loans of 350 million lei ($70m) to five Romanian pension funds, due to accounts being blocked as a result of sanctions.