It is the most successful currency manager in the world. No, we are not talking about the Federal Reserve, we are talking about the Hong Kong Monetary Authority (HKMA).
It has kept the Hong Kong Dollar (HKD) pegged to the U.S. Dollar for almost 33 years now with barely any volatility, trading in a band of HK$ 7.75 to HK$ 7.85 per U.S. dollar. In the last 10 years, it only violated the band once to the downside in 2003 because of the SARS epidemic.

Citigroup