Late yesterday, Australian Eastern Standard Time, National Australia Bank announced plans to sell a minority stake in its US-based subsidiary Great Western Bank via an initial public offering in the US. NAB said in a media release that this course of action was "customary in the US" if "exiting a business via the public markets."The IPO is expected to launch in the fourth quarter of the 2014 calendar year, with timing, pricing and volume and other information to be made available "around the time of launch."NAB's Group chief executive officer, Andrew Thorburn, said the sale of Great Western Bank was consistent with NAB's strategy to focus on its core franchises in Australia and New Zealand. Accordingly, the group plans is to sell its entire ownership of GWB over time.This progressive sale of GWB is expected to increase the group's Common Equity Tier 1 capital ratio. However "recognition and timing of this benefit is subject to APRA's determination," the bank said.Deutsche Bank Securities and BofA Merrill Lynch are acting as joint book-running managers and underwriters.