(2) Our computation of diluted earnings (loss) per share potentially includes our Convertible Senior Notes and our restricted shares and share units. If determined to be dilutive to period earnings, these securities are included in the denominator of our diluted earnings (loss) per share calculation. For purposes of the diluted earnings (loss) per share calculation, we assumed issuance of 0.6 million and 0.5 million restricted shares and share units for the three and twelve months ended December 31, 2012, respectively, and assumed issuance of 22.1 million shares related to the Convertible Senior Notes, respectively for both periods. We assumed issuance of 0.7 million and 0.9 million restricted shares and share units for the three and twelve months ended December 31, 2011, respectively, and assumed issuance of 19.9 million shares related to the Convertible Senior Notes, respectively for both periods.
(3) Adjusted EBITDA represents earnings before interest expense and other financing costs, amortization of loan fees, provision for income taxes, depreciation, amortization, maintenance turnaround expense, and certain other non-cash income and expense items. However, Adjusted EBITDA is not a recognized measurement under United States generally accepted accounting principles ("GAAP"). Our management believes that the presentation of Adjusted EBITDA is useful to investors because it is frequently used by securities analysts, investors, and other interested parties in the evaluation of companies in our industry. In addition, our management believes that Adjusted EBITDA is useful in evaluating our operating performance compared to that of other companies in our industry because the calculation of Adjusted EBITDA generally eliminates the effects of financings, income taxes, the accounting effects of significant turnaround activities (that many of our competitors capitalize and thereby exclude from their measures of EBITDA), and certain non-cash charges that are items that may vary for different companies for reasons unrelated to overall operating performance.
Adjusted EBITDA has limitations as an analytical tool, and you should not consider it in isolation, or as a substitute for analysis of our results as reported under GAAP. Some of these limitations are:
- Adjusted EBITDA does not reflect our cash expenditures or future requirements for significant turnaround activities, capital expenditures, or contractual commitments;
- Adjusted EBITDA does not reflect the interest expense or the cash requirements necessary to service interest or principal payments on our debt;
- Adjusted EBITDA does not reflect changes in, or cash requirements for, our working capital needs; and
- Adjusted EBITDA, as we calculate it, may differ from the Adjusted EBITDA calculations of other companies in our industry, thereby limiting its usefulness as a comparative measure.
Because of these limitations, Adjusted EBITDA should not be considered a measure of discretionary cash available to us to invest in the growth of our business. We compensate for these limitations by relying primarily on our GAAP results and using Adjusted EBITDA only supplementally. The following table reconciles net income (loss) to Adjusted EBITDA for the periods presented:
|Three Months Ended||Twelve Months Ended|
|December 31,||December 31,|
|Net income (loss)||$207,587||$(64,557)||$398,885||$132,667|
|Interest expense and other financing costs||17,419||33,410||81,349||134,601|
|Amortization of loan fees||1,641||2,057||6,860||8,926|
|Provision for income taxes||114,773||(40,247)||218,202||69,861|
|Depreciation and amortization||24,799||30,594||93,907||135,895|
|Maintenance turnaround expense||13,763||1,107||47,140||2,443|
|Loss and impairments on disposal of assets, net (a)||—||450,796||—||450,796|
|Loss on extinguishment of debt||—||29,695||7,654||34,336|
|Unrealized loss (gain) on commodity hedging transactions (b)||(81,519)||(298,199)||229,672||(183,286)|