The bank, spun off from Lloyds but still dependent on it for much support, claims it is the "only bank which focuses solely on its customers in Britain and nowhere else" and that it "only serves local customers and businesses and not big corporations".
A survey for TSB found 74% of customers said they cared about how and where their bank operates, but 68% were unaware if their bank was involved in investment banking and 22% did not realise their bank loaned money to big corporations.
TSB says it is helping local firms by providing space in branches for small businesses and customers, and paying customers' stamp duty when they take a TSB mortgage. The bank says it "refuses to have an investment banking arm or to use its customers' savings to fund overseas speculation".
TSB chief executive Paul Pester said: "We want consumers to ask their bank to explain how they operate and how they use their customers' money as we believe people have a right to know."