On January 26, 2018, the government retired the protected and subsidized 10 Bs.F per US$1 exchange rate that was highly overvalued as a result of rampant inflation. On February 5, 2018, the Central Bank of Venezuela announced a devaluation, with the exchange rate going to 25,000 Bs.F per USD. This made the bolívar fuerte the second-least valued circulating currency in the world based on the official exchange rate, behind only the Iranian rial, and between September 2017 and August 2018, according to the informal exchange rate, the bolívar fuerte was the least valued circulating currency unit in the world.