Westpac's retail brands have lost share over the years, with the St George and BankSA additions from 2008 proving to be no great contributors to the group. A bespoke Roy Morgan view, compiled for Banking Day, shows a decline in the percentage of Australians nominating one of the Westpac brands as a financial institution where they have a banking service.A recent peak for Westpac was in 2011, when the group's principal banking brand held 19.3 per cent market share. By March 2016 this had dropped to 17.4 per cent after a steady decline over three years.The market share of the NSW-centred subsidiary St George Bank was at a peak of a 9.1 per cent in 2008 before its then CEO defected to a predator. The nadir for St George was in mid-2015 when market share dropped to seven per cent. It has now clawed its way back to 7.6 per cent.BankSA reached a market share peak in 2007 of around two per cent, before Westpac wrapped its control across all St George group brands after the following year's merger. BankSA now kicks along at 1.5 per cent.Bank of Melbourne is one brand trending toward its goals, with its national share now 1.1 per cent.BT is another brand doing better, and is used to some degree, Roy Morgan found, by more than two per cent of Australians.Rams reached pre-GFC heights of a 0.5 per cent share in late 2007. Wrecked by the crisis and the brand saved by Westpac, this once lively mortgage brand now rates a 0.3 per cent share.Across all brands, a present day Westpac market share of 27.2 per cent is more than 200 basis points lower than the bank's 2012 peak of 29.3 per cent. Viewed through the lens of APRA data, Westpac reveals a corresponding pattern since its union with St George.Using home loans as the proxy, Westpac's market share of 25.1 per cent at March 2016 is a measure that's been stable for more than two years. It's in fact much the same as the pre-merger shares of Westpac and St George combined.At one point in early 2010 Westpac lifted its market share to 26.7 per cent but by choice or circumstance has since conceded 160 bps to rivals.The multi-brand strategy at Westpac is one adopted in the mid 1990s under the leadership of then CEO Bob Joss. Successors David Morgan, Gail Kelly and now Brian Hartzer have embraced, extended, and, one guesses, begun to question the utility of it all. Other than its own legacy as a joint stock pioneer as the Bank of New South Wales, most of Westpac's associated brands have mutual roots that have surrendered the tight customer engagement that is still evident in those modern day small ADIs that have persisted with a co-operative ethos.The lowly rating of Westpac on customer satisfaction and brand engagement must be one measure driving strategic rethinks at the bank. The Wales. That banking icon must be returning for a 200th anniversary celebration.