Rothesay Life PLC agreed to a £520 million pensioner-only buy-in with the Cadbury Mondelēz Pension Fund, covering payments for about 1,900 pensioners.
The bulk annuity transaction covers a representative subset of the liabilities for pensions already in payment.
The second tranche of de-risking takes the scheme's insurance to about 20% of £4.6 billion total liabilities, which follows a £500 million buy-in completed in 2009.
The trustees of the pension fund were advised by Aon and Pinsent Masons. Rothesay Life was advised by Gowling WLG.