Keystone Bank Limited, commonly referred to as Osy's Bank, is a commercial bank in Nigeria. The bank is one of the commercial banks licensed by the Central Bank of Nigeria, the national banking regulator.On Friday 5 August 2011, Keystone Bank Limited was issued a commercial banking license by the Central Bank of Nigeria (CBN). On the same day, CBN revoked the banking license of Bank PHB. Keystone Bank assumed the assets and some liabilities of the now defunct Bank PHB. On 22 March 2017, Asset Management Company of Nigeria announced that Keystone bank had been sold to investors for 25 billion naira ($81.5 million). It was sold to Sigma Golf-Riverbank consortium.