Annuity in which premium payments are used to purchase accumulation units, their number depending on the value of each unit. The value of a unit is determined by the value of the portfolio of stocks in which the insurance company invests the premiums. At the time of the payment of benefits to the annuitant, the accumulation units are converted to a monthly fixed number of units. The variable element is the dollar value of each unit. For example, assume that the annuitant pays a monthly premium of $100. If the accumulation unit value during one month is $50, two units are purchased. In another month, if the value of the accumulation unit is $25, four units are purchased. In a third month, the value of the unit is $10, resulting in the purchase of 10 units. This allows the market use of the investment strategy of dollar cost averaging. Accumulation units are credited to the annuitant's account, a procedure that is similar to purchasing shares in a mutual fund.
When income benefits are scheduled to begin, total accumulation units are converted to assume 100 income benefit units per month. The value of the income unit will vary according to the company's stock investments; in one month the annuitant's income might be $1000, in another month $500, in another month $1200. Changes in the investment experience by the insurance company are passed on to the annuitant, but the company absorbs fluctuations in expenses and mortality experience.