The ombudsman proposed freezing its levy on financial firms and case fees next year, despite operating costs surging by 14% in the current financial year.
However, the FOS appeared to lay the ground for a major overhaul of its funding structure.
The service said there are “challenges ahead” and that after maintaining the levy and case fees for the past six years – this isn’t “sustainable indefinitely”.
In plans released today, the FOS added: “We know we’ll need a funding model that’s better-suited to the more streamlined and flexible way we’re now resolving complaints.”
Firms get 25 free cases a year before a £550 charge applies.
The FOS expects a total operating income of £230.7m next year, as total operating costs rise to £293.1m, with a levy of £24.5m.
The ombudsman said it welcomes feedback on its plans and budget for next year.
The Financial Conduct Authority (FCA) signs off budgets and is currently consulting on the levy financial firms are to pay in the next financial year.
Mortgage complaints falling
The ombudsman also gave an update on this year’s complaints with projections for next year.
Mortgage complaints have fallen in 207/18, in contrast to other areas of banking and credit, the FOS said.
However, over the past couple years there has also been a significant increase in complaints about short-term lending, such as payday loans.
However, complaints about Payment Protection Insurance (PPI) still make up the bulk of the FOS’s work – ahead of the August 2019 deadline for consumers to submit issues with policies.
Next year, the ombudsman expects to receive 410,000 complaints, of which 250,000 will be related to PPI.
Caroline Wayman, FOS chief executive, said: “Our challenge for 2018/2019 will be to build on our progress – at a time when, quite rightly, expectations of services like ours continue to grow.
“Once again, the feedback we’re getting suggests our flexible approach is overwhelmingly well-received by financial services customers and businesses alike.”