Ros Altmann has stepped down as director general of Saga, the group that offers advice and financial services to the over-fifties, after only two and a half years.
Although Ms Altmann's role was strategic rather than operational, her departure will be a blow as she is a leading advocate for pensioners' rights.
She wants to spend more time in London, rather than at Saga's base in Folkestone, and plans to return to being an independent adviser, a role she previously held for 17 years. "I care about people and policy and still will," she said.
Ms Altmann, 56, has warned of a "crisis" in pensions because of the decline of final-salary schemes and has criticised the Bank of England's quantitative easing programme, arguing that it contributes to inflation and hurts savers.
Saga faces its own challenges. Its parent company, Acromas, which also owns the Automobile Association, has £4bn of debt and its private equity shareholders, Charterhouse, Permira and CVC, are reportedly looking at a sale.