Santander Bank Polska SA, formerly Bank Zachodni WBK (BZ WBK) (eng. West WBK Bank - the WBK abbreviation below) is a Polish universal bank based in Wrocław, Poznań and Warsaw. It is the third largest bank in Poland in terms of assets value and the number of outlets. It was formed in 2001 by the merger of Bank Zachodni S.A. and Wielkopolski Bank Kredytowy SA. Since 2011, the Bank has been owned by the Spanish bank Santander Group.
On 4 January 2013, Bank Zachodni WBK merged with Kredyt Bank which Santander bought from its Belgian owners KBC Bank. This consolidated its Polish banking business and made Bank Zachodni WBK the third largest bank in Poland by market share. Bank Zachodni WBK has a network of ca. 1000 branches and provides services to 3.5m customers.