Company: RIG
Filing Date: 2025-09-24
Form Type: 424B5
Source: 0001451505-25-000097
Chunk: 35

Company: Transocean Ltd.
Filing Date: 2025-09-24
Form: 424B5
Chunk 35
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, if any, of the U.S. Holder’s adjusted basis in the shares over the fair market value of the shares at the end of the taxable year, but only to the extent of the net amount previously included in income as a result of the mark-to-market election. A U.S. Holder’s basis in its shares would be adjusted to reflect any such income or loss recognized. Gain recognized on the sale, exchange, or other disposition of shares would be treated as ordinary income, and any loss recognized on the sale, exchange, or other disposition of shares would be treated as ordinary loss to the extent such loss does not exceed the net mark-to-market gains previously included in income by the U.S. Holder. Because the mark-to-market election applies only to marketable stock, however, it would generally not apply to a U.S. Holder’s indirect interest in any of our subsidiaries that were determined to be PFICs.

If we are treated as a PFIC for any taxable year, a U.S. Holder that does not make either a QEF election or a mark-to-market election for that year would be subject to adverse tax rules with respect to (i) any excess distribution

<div align='center'>S-21</div>

(generally, the portion of any distributions received by the U.S. Holder with respect to the shares in a taxable year in excess of 125% of the average annual distributions received by the U.S. Holder with respect to the shares in the three preceding taxable years or, if shorter, the U.S. Holder’s holding period for the shares) and (ii) any gain realized on the sale, exchange, or other disposition of the shares. Under these special rules:

| ● | the excess distribution or gain would be allocated ratably over the U.S. Holder’s aggregate holding period in the shares; |

| ● | the amount allocated to the current taxable year, and any taxable year before the first taxable year in which we are a PFIC, would be taxed as ordinary income in the current year; and |

| ● | the amount allocated to each of the other taxable years would be subject to tax at the highest rate of tax on ordinary income in effect for the applicable class of taxpayer for that year, and an interest charge for the deemed tax deferral benefit would be imposed on the resulting tax liability as if that tax liability had been due for each such other taxable year. |

Unless a U.S. Holder either (i) makes a timely QEF election or mark-to-market election