Montreal-headquartered National Bank has been the best performing amongst the group, doubling over the last five years and up 56% over the last year. Having grown by taking over Canadian Western Bank (CWB), the eighth-largest bank in Canada, for $5 billion, it subsequently bought the retail business of Quebec-based Laurentian Bank with its $10.9 billion in assets and $1.4 billion in small- and medium-sized enterprise loans.