The Group’s reported results could be adversely affected by the impairment of assets and goodwill.

An asset impairment charge may result from the occurrence of unexpected adverse events that impact the Group’s expected performances. In accordance with IFRS, the Group does not amortise goodwill but rather tests it annually for impairment: such impairments cannot be reversed.

The Group will continue to test goodwill and may, in the future, record additional impairment charges. This could result in the recognition of impairment provisions (which are non cash items) that could be significant and could have an adverse effect on the Group’s reported results.

The Group’s net earnings are sensitive to the assumptions used for valuing defined benefit pension plans and post retirement healthcare plans.

Certain of the Group’s businesses sponsor defined benefit pension plans. The pension expense reported for these plans is sensitive to the assumptions used to value the pension obligations, and also to the underlying economic conditions that influence the assumptions. Changing economic conditions, particularly poor pension investment returns, may require the Group to make substantial cash contributions to its pension plans.

Actual investment returns achieved compared to the amounts assumed within the Group’s reported pension expense are reported in the table below (amounts for prior years have been adjusted to exclude defined contribution assets as explained in note 50 to the financial statements).

As at 31 December 2009, the Group had estimated pension liabilities (on an IAS19 accounting basis) of US$16.2 billion and assets of US$12.4 billion. After excluding those pension arrangements deliberately operated as unfunded arrangements, representing liabilities of US$1.1 billion, the global funding level for pension liabilities (on an IAS19 basis) was approximately 82 per cent. If the funding level materially deteriorates further, cash contributions from the Group may be needed, subject to local requirements.