The Charity Commission is to spend £1.85m transferring its 120 London staff to new offices, it revealed last week.
The commission, whose budget is frozen, has accumulated the money over the past five years from efficiency savings, mainly job losses. It currently employs about 480 staff, compared with 610 five years ago.
The regulator wants to move to Fox Court on London's Gray's Inn Road when its lease on nearby Harmsworth House expires in June next year, but it has yet to sign a contract.
Simon Carney, head of governance at the commission, said it had been putting aside money to meet refurbishment costs, such as building work and professional fees. He said Fox Court was a third of the size of Harmsworth House and would save the commission up to £1.4m a year.
He said the regulator, which also has staff in Liverpool, Taunton and Newport, south Wales, had realised in 2004 that it needed to "squirrel money away" because of pressure on funding.