Note 6—Income Taxes

Tax rate—Transocean Ltd., a holding company and Swiss resident, is exempt from cantonal and communal income tax in Switzerland, but is subject to Swiss federal income tax. At the federal level, qualifying net dividend income and net capital gains on the sale of qualifying investments in subsidiaries are exempt from Swiss federal income tax. Consequently, Transocean Ltd. expects dividends from its subsidiaries and capital gains from sales of investments in its subsidiaries to be exempt from Swiss federal income tax.

Our provision for income taxes is based on the tax laws and rates applicable in the jurisdictions in which we operate and earn income. The relationship between our provision for or benefit from income taxes and our income or loss before income taxes can vary significantly from period to period considering, among other factors, (a) the overall level of income before income taxes, (b) changes in the blend of income that is taxed based on gross revenues rather than income before taxes, (c) rig movements between taxing jurisdictions and (d) our rig operating structures. Generally, our annual marginal tax rate is lower than our annual effective tax rate.

In the six months ended June 30, 2014 and 2013, our estimated annual effective tax rates were 13.8 percent and 21.7 percent, respectively. These rates were based on estimated annual income before income taxes for each period after adjusting for various discrete items, including certain immaterial adjustments to prior period tax expense. See Note 17—Subsequent Events.

Unrecognized tax benefits—The liabilities related to our unrecognized tax benefits, including related interest and penalties that we recognize as a component of income tax expense, were as follows (in millions):

	June 30, 2014		December 31, 2013
Unrecognized tax benefits, excluding interest and penalties	$	330	$	326
Interest and penalties	169		176
Unrecognized tax benefits, including interest and penalties	$	499	$	502

In the year ending December 31, 2014, it is reasonably possible that our existing liabilities for unrecognized tax benefits may increase or decrease primarily due to the progression of open audits or the expiration of statutes of limitation. However, we cannot reasonably estimate a range of potential changes in our existing liabilities for unrecognized tax benefits due to various uncertainties, such as the unresolved nature of various audits.

Tax returns—We file federal and local tax returns in several jurisdictions throughout the world. With few exceptions, we are no longer subject to examinations of our U.S. and non-U.S. tax matters for years prior to 2010.

Our tax returns in the major jurisdictions in which we operate, other than the U.S., Norway and Brazil, which are mentioned below, are generally subject to examination for periods ranging from three to six years. We have agreed to extensions beyond the statute of limitations in two major jurisdictions for up to 19 years. Tax authorities in certain jurisdictions are examining our tax returns and in some cases have issued assessments. We are defending our tax positions in those jurisdictions. While we cannot predict or provide assurance as to the outcome of these proceedings, we do not expect the ultimate liability to have a material adverse effect on our consolidated statement of financial position or results of operations, although it may have a material adverse effect on our consolidated statement of cash flows.

U.S. tax investigations—During the six months ended June 30, 2014, we received an assessment from the U.S. tax authorities related to our 2010 and 2011 U.S. federal income tax returns. The significant issue raised in the assessment relates to transfer pricing for certain charters of drilling rigs between our subsidiaries. This issue, if successfully challenged, would result in net adjustments of approximately $290 million of additional taxes, excluding interest and penalties. An unfavorable outcome on these adjustments could result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. Furthermore, if the authorities were to continue to pursue these positions with respect to subsequent years and were successful in such assertions, our effective tax rate on worldwide earnings with respect to years following 2011 could increase substantially, and could have a material adverse effect on our consolidated results of operations or cash flows. We believe our U.S. federal income tax returns are materially correct as filed, and we intend to continue to vigorously defend against all such claims to the contrary.

Norway tax investigations and trial—Norwegian civil tax and criminal authorities are investigating various transactions undertaken by our subsidiaries in 1999, 2001 and 2002 as well as the actions of certain employees of our former external tax advisors on these transactions. The authorities issued tax assessments as follows: (a) NOK 684 million, equivalent to approximately $114 million, plus interest, related to the migration of our subsidiary that was previously subject to tax in Norway, (b) NOK 412 million, equivalent to approximately $69 million, plus interest, related to a 2001 dividend payment and (c) NOK 43 million, equivalent to approximately $7 million, plus interest, related to certain foreign exchange deductions and dividend withholding tax. We provided a parent company guarantee in the amount of NOK 699 million, equivalent to approximately $117 million with respect to one of these tax disputes. In November 2012, the Norwegian district court in Oslo heard the civil tax case regarding the disputed tax assessment of NOK 684 million related to the migration of our subsidiary. On March 1, 2013, the Norwegian district court in Oslo overturned the initial civil tax assessment and ruled in our favor, and the tax authorities filed an appeal. On June 26, 2014, the Norwegian district court in Oslo ruled that our subsidiary was liable for the civil tax assessment of NOK 412 million, equivalent to approximately $69 million, but waived all penalties and interest. We intend to file an appeal and to take other appropriate action to continue to support our position that our Norwegian tax returns are materially correct as filed.

In June 2011, the Norwegian authorities issued criminal indictments against two of our subsidiaries alleging misleading or incomplete disclosures in Norwegian tax returns for the years 1999 through 2002, as well as inaccuracies in Norwegian statutory financial statements for the years ended December 31, 1996 through 2001. Two employees of our former external tax advisors were also issued criminal indictments with respect to the disclosures in our tax returns, and our former external Norwegian tax attorney was issued criminal indictments related to certain of our restructuring transactions and the 2001 dividend payment. In January 2012, the Norwegian authorities supplemented the previously issued criminal indictments by issuing a financial claim of NOK 1.8 billion, equivalent to approximately $300 million, jointly and severally, against our two subsidiaries, the two external tax advisors and the external tax attorney. In February 2012, the authorities dropped the previously existing civil tax claim related to a certain restructuring transaction. In April 2012, the Norwegian tax authorities supplemented the previously issued criminal indictments against our two subsidiaries by extending a criminal indictment against a third subsidiary, alleging misleading or incomplete disclosures in Norwegian tax returns for the years 2001 and 2002. The criminal trial commenced in December 2012. In May 2013, the Norwegian authorities dropped the financial claim of NOK 1.8 billion against one of our subsidiaries and the criminal case related to the migration case of another subsidiary. The criminal trial proceedings ended in September 2013. The Norwegian authorities subsequently suggested, if we were found guilty, that the court assess criminal penalties of NOK 230 million, equivalent to approximately $38 million, against three of our subsidiaries in addition to any civil tax penalties and the financial claim. We believe our Norwegian tax returns are materially correct as filed, and we intend to continue to vigorously contest any assertions to the contrary by the Norwegian civil and criminal authorities in connection with the various transactions being investigated. An unfavorable outcome on the Norwegian civil or criminal tax matters could result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. See Note 17—Subsequent Events.

Brazil tax investigations—Certain of our Brazilian income tax returns for the years 2000 through 2004 are currently under examination. In December 2005, the Brazilian tax authorities issued an aggregate tax assessment of BRL 694 million, equivalent to approximately $315 million, including a 75 percent penalty and interest. On January 25, 2008, we filed a protest letter with the Brazilian tax authorities, and we are currently engaged in the appeals process. On May 19, 2014, with respect to our Brazilian income tax returns for the years 2009 and 2010, the Brazilian tax authorities issued an aggregate tax assessment of BRL 121 million, equivalent to approximately $55 million, including a 75 percent penalty and interest. On June 18, 2014, we filed a protest letter with the Brazilian tax authorities. We believe our returns are materially correct as filed, and we are vigorously contesting these assessments. An unfavorable outcome on these proposed assessments could result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows.

Other tax matters—We conduct operations through our various subsidiaries in a number of countries throughout the world. Each country has its own tax regimes with varying nominal rates, deductions and tax attributes. From time to time, we may identify changes to previously evaluated tax positions that could result in adjustments to our recorded assets and liabilities. Although we are unable to predict the outcome of these changes, we do not expect the effect, if any, resulting from these adjustments to have a material adverse effect on our consolidated statement of financial position, results of operations or cash flows.