4.3.3Revenue

The Company’s revenue mainly originates from construction contracts and lease and operate contracts. Revenue originating from construction contracts is presented in the Turnkey segment while revenue from lease and operate contracts is presented in the Lease and Operate segment. Around 60% of the Company’s 2019 lease and operate revenue is made of charter rates related to lease contracts while the remaining amount originates from operating contracts.

The Company’s policy regarding revenue recognition is described in further detail in note 4.2.7 B. Critical Accounting Policies − (e) Revenue. For the disaggregation of total revenue by country and by segment, please refer to Geographical Information under note 4.3.2 Operating Segments and Directional Reporting.

The Company recognizes most of its revenue (more than 95%) over time. The Company’s construction contracts can last for multiple years depending on the type of product, scope and complexity of the project while the Company’s Lease and Operate contracts are generally multiple-year contracts. As a result, the Company has (partially) outstanding performance obligations to its clients (unsatisfied performance obligations) at December 31, 2019. These unsatisfied performance obligations relate to:

• Ongoing construction contracts, including the construction of vessels under finance lease that still need to be completed;
• Ongoing multiple-year operating contracts. Note that for the specific disclosure on unsatisfied performance obligations, the lease component of the Lease and Operate contracts is excluded (this component being described in further detail in notes 4.3.13 Property, Plant and Equipment and 4.3.15 Finance Lease Receivables).

The following table presents the unsatisfied performance obligations as at December 31, 2019 (in billions of US$):

The unsatisfied performance obligations for the committed construction contracts relate mostly to four major construction contracts (three FPSO's and one TMS). Revenue related to these construction contracts is expected to be recognized over the coming three years in line with the construction progress on these projects.

The unsatisfied performance obligations for the operating contracts relate to i) the Company’s vessels leased to clients where the Company is the operator (both operating and finance lease contracts) and ii) one operating contract for operating services on a vessel that is owned by the client. The operating contracts end between 2021 and 2036. The Company will recognize the unsatisfied performance obligation over this period in line with the work performed.

The Company can agree on various payment arrangements which generally reflect the progress of delivered performance obligations. However, if the Company’s delivered performance obligation exceeds instalments invoiced to the client, a ‘Construction work-in-progress‘ (contract asset) is recognized (see note 4.3.20 Construction Work-In-Progress). If the instalments invoiced to the client exceed the work performed, a contract liability is recognized (see note 4.3.27 Trade and Other Payables).

As a result of various commercial discussions with clients, the Company recognized revenue amounting to US$16 million in 2019 (2018: US$23 million) originating from performance obligations satisfied in previous periods.

Lease revenue recognized for leases where the Company is the lessor, for both operating and finance leases, relates to fixed and variable lease payments. Most of the Company's revenue from lease contracts is based on fixed day rates. However, some of the contracts consist of performance-based payments. These are variable lease payments that do not depend on an index or a rate, and are excluded from the measurement of the lease payments receivable. The amount of performance-related lease payments for 2019 was US$24 million (2018: US$47 million).