In 1998, the global financial crisis started and the Russian government defaulted on its debts, rouble was dramatically devaluated. Kasyanov was the head of the working team for restructuring Russian government external debts and of the private banks of the country. At the same time he negotiated with Russian creditors for restructuring domestic debts. Kasyanov negotiated with the International Monetary Fund which granted favourable perspectives for reaching profitable agreements for Russia. As a result of this, the rouble rate was stabilised, which in its own turn helped reduce the inflation and restored production and services parts of Russian economy. These successes proved Kasyanov to be a good negotiator: he was called "the principal financial diplomat of the country". In February 1999 he was appointed First Deputy Minister and in May 1999 President Yeltsin appointed Kasyanov Minister of Finance of the Russian Federation.