QGOG CONSTELLATION S.A. IPO

We estimate that our net proceeds from this offering, after deducting the
underwriting discount and estimated offering expenses, will be approximately
$517.8 million (or approximately $596.8 million if the underwriters exercise
their option to purchase additional common shares in full), assuming the shares
are offered at $20.00 per share, the mid-point of the estimated offering price
range set forth on the cover page of this prospectus. A $1.00 increase
(decrease) in the assumed initial public offering price of $20.00 per share
would increase (decrease) the net proceeds to us from this offering by
approximately $26.3 million, assuming the number of common shares offered by us
as set forth on the cover page of this prospectus remains the same and after
deducting the underwriting discounts and commissions.

We will not receive proceeds from the concurrent private placement to be
completed upon the closing of this offering. However, upon the closing of the
private placement we will own 100% of the equity interests in Amaralina Star
Ltd. and Laguna Star Ltd.

We intend to use the net proceeds from this offering (1) to make capital 
expenditures and related expenses for certain existing projects, including 
Drillship No. 3, which is under construction and (2) to make capital 
expenditures and investments related to expected new projects, including 
amounts payable following our potential exercise of an option included in a 
letter of intent we have executed with Samsung and related expenses in 
connection therewith and for general corporate purposes. Specifically, we 
expect to allocate the net proceeds as follows: 
                                                                         Estimated net proceeds
Allocation                                      Percentage               (in millions of $) (1)
Capital expenditures for certain                                         
existing projects                                      52.4 %                    271.4         
Capital expenditures for new projects                                    
and general corporate purposes                         47.6 %                    246.4         
                                                                                               
Total                                                   100 %                    517.8         
                                                                                           
(1) Assuming the underwriters do not exercise their option to purchase additional
    common shares.

The oil and gas services industry is highly competitive. We face competition
mainly in offshore drilling from competitors such as Diamond Offshore Drilling,
Inc., Ensco plc, Ocean Rig UDW, Inc., Odebrecht Óleo e Gás S.A., Pacific
Drilling S.A., Petroserv S.A., Seadrill Ltd. and Transocean Ltd. Demand for
contract drilling and related services is influenced by a number of factors,
including the current and expected prices of oil and gas and the expenditures of
oil and gas companies for exploration and development activities. In addition,
demand for drilling and related services remains dependent on a variety of
political and economic factors beyond our control, including worldwide prices
and demand for oil and gas, the ability of OPEC to set and maintain production
levels and pricing, the level of production of non-OPEC countries and the
policies of the various governments regarding exploration and development of
their oil and gas reserves, among others.

We believe we are competitive in terms of pricing, performance, equipment,
safety and availability of experienced, skilled personnel. In addition,
industry-wide shortages of supplies, services, skilled personnel and equipment
necessary to conduct our customers’ businesses can occur. Competition for
offshore rigs is usually on a global basis, as these rigs are mobile and may be
transported at a cost that can be substantial, from one region to another in
response to demand. Our largest competitors in the drilling industry have more
diverse fleets and may have greater financial resources than we do, which may
better enable them to withstand periods of low utilization, compete more
effectively on the basis of price, build new rigs or acquire existing rigs.