The first formal currency swap, as opposed to the then used parallel loans structure, was transacted by Citicorp International Bank for a $US100,000,000 10 year US Dollar Sterling swap between Mobil Oil Corporation and General Electric Corporation Ltd (UK). The concept of the interest rate swap was developed by the Citicorp International Swap unit but cross-currency interest rate swaps were introduced by the World Bank in 1981 to obtain Swiss francs and German marks by exchanging cash flows with IBM. This deal was brokered by Salomon Brothers with a notional amount of $210 million and a term of over ten years.