Construction & Engineering: Remaining performance obligations

• estimates and assumptions in determining our financial results, remaining performance obligations and backlog, including the timing and significance of impairments of long-lived assets, equity or other investments, receivables, goodwill or other intangible assets;

• significant fluctuations in foreign currency rates;

• the recognition of tax impacts related to changes in tax laws or uncertain tax positions; and

• the timing and magnitude of costs we incur to support our operations or growth internally or through acquisitions.

A variety of issues could affect the timing or profitability of our projects, which may result in additional costs to us, reductions or delays in revenues, the payment of liquidated damages or project termination.

Our business is dependent in part upon projects that can be cyclical in nature and are subject to risks of delay or cancellation. The timing of or failure to obtain contracts, delays in awards of, start dates for or completion of projects and the cancellations of projects can result in significant periodic fluctuations in our business, financial condition, results of operations and cash flows. Many of our projects involve complex design, engineering, financing, permitting, right of way acquisition, procurement and construction phases that occur over extended time periods, sometimes several years, and we have encountered and may in the future encounter project delays, additional costs or project performance issues as a result of, among other things:

• inability to meet project schedule requirements or achieve guaranteed performance or quality standards for a project, which can result in increased costs, through rework, replacement or otherwise, or the payment of liquidated damages to the customer or contract termination;

• failure to accurately estimate project costs or accurately establish the scope of our services;

• failure to make judgments in accordance with applicable professional standards (e.g., engineering standards);

• unforeseen circumstances or project modifications not included in our cost estimates or covered by our contract for which we cannot obtain adequate compensation, including concealed or unknown environmental, geological or geographical site conditions or technical problems such as design or engineering issues;

• changes in laws or permitting and regulatory requirements during the course of our work;

• delays in the delivery or management of design or engineering information, equipment or materials;