The kina, introduced several months before Papua New Guinea gained independence, is the country’s currency. The central bank is the Bank of Papua New Guinea. The value of the kina increased greatly following independence, but the secession crisis in Bougainville in 1989 and poor fiscal control resulted in major devaluation through the 1990s. Over the next decade, responsible financial management was restored and the central bank strengthened. Papua New Guinea has had a small stock exchange since the late 1990s, but many of the companies traded—chiefly mining, oil, and financial concerns—are foreign-based.