This was followed by the 1990 purchase of Central Banking Systems; the 1991 purchase of 30 branches in northern California from failed Imperial Savings and Loan; the 1992 purchase of Atlantic Financial Federal Savings Bank from the Resolution Trust Corporation; the 1993 purchase of 15 branches in northern California from Citibank for $360 million; the 1995 purchase of NorthBay Savings Bank, headquartered in Petaluma, California; and the 1997 purchase of branches from Bank of America and Coast Federal Bank.