This excerpt taken from the HIT 6-K filed Nov 16, 2009.
Hitachi is responsible for a significant amount of employee retirement benefit costs that are based on a number of assumptions.
Hitachi has a significant amount of employee retirement benefit costs that it derives from actuarial valuations based on a number of assumptions. Inherent in these valuations are key assumptions used in estimating pension costs including mortality, withdrawal and retirement rates, changes in wages, the discount rate and expected return on plan assets. Hitachi is required to make judgments regarding the key assumptions by taking into account various factors including personnel demographics, market conditions and expected trends in interest rates. Although management believes that its key assumptions are reasonable in light of the various underlying factors, there can be no assurance that the key assumptions will correspond to actual results. If Hitachis key assumptions differ from actual results, the consequent deviation of actual pension costs from estimated costs may have a material adverse effect on its financial condition and results of operations. A decrease in the discount rate may result in an increase in the amount of the actuarial loss which Hitachi amortizes into income over the service lives of its employees. In addition, Hitachi may change these key assumptions, such as the discount rate or the expected return on plan assets. Changes in key assumptions may also have a material adverse effect on Hitachis financial condition and results of operations.