National Australia Bank will go looking for a capital lift in excess of A$2 billion, through a partial and then a full sell down of its US banking subsidiary Great Western Bank.Great Western had US$2.1 billion in net equity at June 2014, the bank said in a preliminary filing with the US Securities and Exchange Commission.It had US$9.3 billion in assets and 1500 staff. Assets have doubled since NAB acquired the South Dakota lender in early 2008. The bank has in turn acquired some small, struggling and mostly urban lenders since then.NAB's annual report described the bank as the "seventh largest agribusiness lender" in the US, though loans to this sector comprised only one quarter of receivables.Its net income was US$77.1 million for the nine months ended June 2014 and US$96.2 million for the 12 months ended September 2013.Acquired in 2008, NAB promoted Great Western as the cornerstone of an agribusiness banking expansion strategy in the United States, but little further was heard of this strategy.The Great Western sale will lift NAB's core capital to around A$50 billion.