353 Renewal of a contract  is when a policyholder takes whatever  action is required, typically payment of a premium, in order to  maintain benefits under the contract.  Spread  is the difference between the current bid and the current  ask or offered price of a given security. Stochastic modeling  is a statistical process that uses probability  and random variables to predict a range of probable investment  performances.  Repurchase agreement  is a sale of securities with an agreement  to buy back the securities at a specified time and price. Residential Mortgage Backed Security (RMBS)  is an asset- backed security that is secured by a mortgage or collection of  mortgages.  Temporary differences  are differences between the carrying  amount of an asset or liability in the statement of financial  position and its tax base that will reverse over time. Trade date  is the date that an entity commits itself to purchase  or sell an asset. Transaction costs  are incremental costs that are directly  attributable to the acquisition, issue or disposal of a financial  asset or liability. Return on plan assets  is the investment income derived from  plan assets, together with realized and unrealized gains and  losses on the plan assets less any costs of administering the  plan and less any tax payable by the plan itself. Reverse repurchase agreement  is a purchase of securities with  the agreement to resell them at a later specified date and price. Security lending  involves a loan of a security from one party to  another.  Settlement date  is the date that a financial asset is delivered to  the entity that purchased it. Solvency II  is the fundamental reform of European insurance  solvency and risk governance legislation. Sovereign exposures  relates to government issued securities  including Dutch Government bonds and US Treasury, agency and  state bonds. Spot exchange rate  is the exchange rate for immediate delivery. Trust Pass-Through securities  are securities through which the  holders participate in a trust. The assets of these trusts consist  of debentures issued by an Aegon Group company. Unlocking  of DPAC and VOBA refers to the process of updating  the DPAC or the VOBA amortization schedule to reflect changes  between the past and current expectations of key assumptions  used in the projection of future gross profits.  Value of Business Acquired (VOBA)  the difference between the  fair value and the carrying amount of the insurance liabilities  recognized when a portfolio of insurance contracts is acquired  (directly from another insurance company or as part of a  business combination).