Ladbrokes has begun a consultation to close its defined benefit (DB) pension scheme to future accrual.
Its final salary scheme closed to new members in 2007.
The betting organisation is anticipating contributions of £9.2 million this year to help reduce its deficit.
The cost of running the scheme stands at £62,500 a month.
In 2012, the organisation launched a master-trust pension scheme to comply with auto-enrolment.
A spokesperson for Ladbrokes said: “We are undertaking a full consultation and it will comment further when that process is complete.”