The agency stopped working on the account in March having held the business for the past two years. Sainsbury's has said that it will not be looking for a replacement, although sources have suggested it may be looking for an agency to handle a brief for its credit-card business.
A plan by the bank to align its marketing with the supermarket's "try something new today" strategy is likely to mark the end for Little Bill, the animated receipt.
In March this year, before the release of Sainsbury's Bank's disappointing results, Tim Pile, the company's chief executive who hired Chick Smith Trott, quit the company.
He was replaced last month when the bank, which is part-owned by Halifax Bank of Scotland, appointed the former head of credit risk at HSBC, Rob Walker.