Key Assumptions The calculation of policy and claim reserves involves numerous assumptions, but the primary assumptions used to calculate reserves are (1) the discount rate, (2) the claim resolution rate, and (3) the claim incidence rate for policy reserves and IBNR claim reserves. Of these assumptions, our discount rate and claim resolution rate assumptions have historically had the most significant effects on our level of reserves because many of our product lines provide benefit payments over an extended period of time. 1. The  discount rate , which is used in calculating both policy reserves and incurred and IBNR claim reserves, is the interest rate that we use to discount future claim payments to determine the present value. A higher discount rate produces a lower reserve. If the discount rate is higher than our future investment returns, our invested assets will not earn enough investment income to support our future claim payments. In this case, the reserves may eventually be insufficient. We set our assumptions based on our current and expected future investment yield of the assets supporting the reserves, considering current and expected future market conditions. If the investment yield on new investments that are purchased differs from the investment yield of the existing investment portfolio, the discount rate assumption on claims may be adjusted to reflect the impact of the new investment yield. 2. The  claim resolution rate , used for both policy reserves and incurred and IBNR claim reserves, is the probability that a disability or long-term care claim will close due to recovery or death of the insured. It is important because it is used to estimate how long benefits will be paid for a claim. Estimated resolution rates that are set too high will result in reserves that are lower than they need to be to pay the claim benefits over time. Claim resolution assumptions involve many factors, including the cause of disability, the policyholder's age, the type of contractual benefits provided, and the time since initial disability. We primarily use our own 42 December 31, 2018 Gross Total Reinsurance Ceded Policy Reserves Claim Reserves Total Net % Incurred IBNR % Total Group Disability $ —  —  % $ 5,900.0  $ 670.8  28.4  % $ 6,570.8  $ 71.0  $ 6,499.8  Group Life and Accidental Death & Dismemberment 52.9  0.3  750.7  217.8  4.2  1,021.4  7.1  1,014.3  Individual Disability 518.4  2.6  1,357.8  137.1  6.4  2,013.3  217.1  1,796.2  Voluntary Benefits 1,643.9  8.1  49.0  58.1  0.5  1,751.0  27.1  1,723.9  Dental and Vision —  —  0.1  14.5  0.2  14.6  0.2  14.4  Unum US Segment 2,215.2  11.0  8,057.6  1,098.3  39.7  11,371.1  322.5  11,048.6  Unum International Segment 175.7  0.9  1,838.4  115.0  8.4  2,129.1  84.6  2,044.5  Colonial Life Segment 2,112.5  10.5  292.6  131.4  1.8  2,536.5  8.0  2,528.5  Individual Disability 332.2  1.6  9,085.0  199.6  40.1  9,616.8  1,646.6  7,970.2  Long-term Care 9,463.2  46.9  1,787.6  235.7  8.7  11,486.5  39.9  11,446.6  Other 5,869.5  29.1  187.6  120.2  1.3  6,177.3  5,119.8  1,057.5  Closed Block Segment 15,664.9  77.6  11,060.2  555.5  50.1  27,280.6  6,806.3  20,474.3  Subtotal $ 20,168.3  100.0  % $ 21,248.8  $ 1,900.2  100.0  % 43,317.3  7,221.4  36,095.9  Adjustment Related to Unrealized Investment Gains and Losses 3,220.3  261.4  2,958.9  Consolidated $ 46,537.6  $ 7,482.8  $ 39,054.8 