income (a GAAP measure) to pre-tax income, adjusted for special items (a non-GAAP financial measure). We adjust pre-tax income for the following items to determine pre-tax income, adjusted for special items, for the reasons described below:

•	MTM adjustments and settlements. MTM adjustments are defined as fair value changes recorded in periods other than the settlement period. Such fair value changes are not necessarily indicative of the actual settlement value of the underlying hedge in the contract settlement period. Settlements represent cash received or paid on hedge contracts settled during the period. These items adjust fuel expense to show the economic impact of hedging, including cash received or paid on hedge contracts during the period. Adjusting for these items allows investors to better understand and analyze our core operational performance in the periods shown.

•	Restructuring and other. Because of the variability in restructuring and other, the adjustment for this item is helpful to investors to analyze our recurring core performance in the periods shown.

•	Loss on extinguishment of debt. We adjusted for loss on extinguishment of debt in 2014 to assist investors with their analysis of our recurring core financial performance.

•	Virgin Atlantic MTM adjustments . We record our proportionate share of earnings from our equity investment in Virgin Atlantic in other expense. We adjust for Virgin Atlantic's MTM adjustments to allow investors to better understand and analyze our core financial performance in the periods shown.

The following table shows a reconciliation of CASM (a GAAP measure) to CASM-Ex (a non-GAAP financial measure). We adjust CASM for the following items to determine CASM-Ex for the reasons described below:

•	Aircraft fuel and related taxes. The volatility in fuel prices impacts the comparability of year-over-year financial performance. The adjustment for aircraft fuel and related taxes (including our regional carriers) allows investors to better understand and analyze our non-fuel costs and year-over-year financial performance.

•	Profit sharing. We adjust for profit sharing because this adjustment allows investors to better understand and analyze our recurring cost performance and provides a more meaningful comparison of our core operating costs to the airline industry.

•	Restructuring and other. Because of the variability in restructuring and other, the adjustment for this item is helpful to investors to analyze our recurring core performance in the periods shown.

•	Other expenses. Other expenses include aircraft maintenance and staffing services we provide to third parties, our vacation wholesale operations and refinery cost of sales to third parties. Because these businesses are not related to the generation of a seat mile, we adjust for the costs related to these sales to provide a more meaningful comparison of the costs of our airline operations to the rest of the airline industry.

The following table shows a reconciliation of ROIC. We present ROIC as management believes this metric is helpful to investors in assessing our ability to generate returns using its invested capital. ROIC is operating