Dual track for NAB US bank sale 06 October 2014 4:42PM Ian Rogers Major Banks, NAB The milestones for an initial public offer of NAB's Great Western Bank continue to be met, even as NAB considers an offer from a trade buyer.Late on Friday, NAB said it would sell 16 million shares through an initial public offering at a price range of US$21 to US$24, valuing the bank US$1.3 billion. NAB paid more than US$500 million for GWB in late 2007.The bank is yet to confirm Banking Day's report on Friday that a sale to a trade buyer is in the works.The shares for sale under the IPO represent 27.6 per cent of GWB stock. NAB will also grant the underwriters (Deutsche Bank and Bank of America - Merrill Lynch) a 30-day option to purchase up to an additional 2.4 million shares of GWB's common stock.