Lighthouse Group has signed a three year advice contract with the Bakers Food and Allied Workers Union (BFAWU).
The union's 23,000 members can now use the advisory group for financial advice.
The deal is the latest in a series of union contracts won by the group. Last week, the Royal College of Nursing also signed a three year deal.
Ian Hodson, national president of BFAWU, commented: "BFAWU looks forward to offering its members financial advice through Lighthouse. We hope this is the start of a long and successful relationship for both parties."
Lighthouse chief executive Malcolm Streatfield said the firm had been targeting large-scale contracts and was pleased with the latest contract.
More than half of people over the age of 55 see financial security as a top priority in retirement, yet a third allocate more time to buying a new car, research from Legal & General (L&G) has found.
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Alongside Barrett, Hopkins, Boston and Thorman on 17 October