First Citizens BancShares in Raleigh, N.C., has finally combined its two main subsidiaries.

The $21 billion-asset company said IronStone Bank, its thrift, merged into First Citizens Bank, a state-chartered bank, on Friday. IronStone, which was used over eight years to expand into states such as Arizona, California and Florida, will remain a division of the bank.

"In addition to the benefits of bringing together the best qualities and strengths of both organizations, this merger will give us significant opportunities for improved efficiencies and growth," Frank Holding Jr., the company's chairman and chief executive, said in a press release Friday.

The IronStone name will remain on branches "for the foreseeable future" and Hope Holding Connell will continue to lead the IronStone division as its president.

First Citizens first applied to merge the units in October 2008 but quickly withdrew the application without saying why. Analysts had speculated in recent years that another attempt to consolidate was possible.

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