Item 1A. Risk Factors.

Our business is subject to a variety of risks and uncertainties that are difficult to predict and many of which are outside of our control. For a detailed discussion of the risks that affect our business, refer to Item 1A. Risk Factors of Part I of our 2020 Annual Report. As of the date of this filing, there have been no material changes to the risk factors previously described in our 2020 Annual Report, except as set forth below with respect to our acquisition of Blattner and except that the potential effects of the acquisition of Blattner, and the financing thereof, may also have the effect of heightening certain other risks described in our 2020 Annual Report. The matters specifically identified are not the only risks and uncertainties facing our company, and additional risks and uncertainties not known to us or not specifically identified may also impair our business. If any of these risks and uncertainties occur, our business, financial condition, results of operations and cash flows could be negatively impacted, which could negatively impact the value of an investment in our company.

We may not realize the anticipated benefits and synergies from our acquisition of Blattner.

The success of our acquisition of Blattner will depend, in part, on our ability to realize the anticipated benefits from successfully integrating Blattner’s business. We plan on devoting substantial management attention and resources to integrating our and Blattner’s business practices and operations so that we can fully realize the anticipated benefits of the acquisition. Nonetheless, the business and assets acquired may not be successful, achieve the anticipated financial results or continue to grow at the same rate as when operated independently or may require greater resources and investments than originally anticipated. The acquisition of Blattner could also result in the assumption of unknown or contingent liabilities. Potential difficulties we may encounter in the integration process include the following:

• the inability to successfully integrate Blattner’s business in a manner that permits us to achieve the strategic operational benefits, additional opportunities with customers, reputational benefits or cost savings anticipated to result from the acquisition, which would result in some anticipated benefits of the acquisition not being realized in the time frame currently anticipated, or at all;

• the failure to integrate operations and internal systems, programs and controls;

• the inability to successfully realize the anticipated value from some of Blattner’s assets;

• lost revenues and lost or damaged commercial relationships;

• the complexities and difficulties associated with our decentralized management structure;

• the additional complexities of integrating a business with a different customer base, markets, history, culture and strategy;

• the failure to retain key employees of either of the two companies that may be difficult to replace;

• the disruption of our ongoing businesses or inconsistencies in our services, standards, controls, procedures and policies;

• potential unknown, unforeseen or greater than expected liabilities and expenses associated with the acquired business;

• changes in estimates related to revenues and costs associated with Blattner's ongoing contracts with customers; and

• performance shortfalls as a result of the diversion of management’s attention caused by integrating Blattner’s operations.

In addition, laws and regulations related to renewable energy could adversely impact our business, financial condition, results of operations and growth prospects of Blattner, including, among other things, changes to legislation and regulation that mandate percentages of power to be generated from renewable sources, require utilities to meet reliability standards, and encourage installation of new electric power transmission and renewable energy generation facilities. Furthermore, supply chain and other logistical difficulties, as well as sourcing restrictions on materials necessary for certain renewable energy projects, could negatively impact renewable energy customers and delay or jeopardize the viability of certain renewable energy projects in the future. For example, delays in the transportation of materials for renewable projects (e.g., solar panels) from ports to project sites, as well as sourcing restrictions on certain solar project materials produced in China, could increase the pricing of such materials, and negatively impact Blattner’s customers and certain solar infrastructure projects in the near term. Any of these risks could adversely affect our ability to fully realize the anticipated benefits of our acquisition of Blattner within the expected timeframe or at all or such benefits may take longer to realize or cost more than expected, which could adversely affect our business, financial condition, results of operations and growth prospects.

We have incurred, and expect to continue to incur, substantial expenses related to our acquisition of Blattner.

We have incurred, and expect to continue to incur, substantial expenses in connection with the acquisition of Blattner and integrating the business, operations, practices, policies and procedures of Blattner. While we assumed that a certain level of transaction and integration expenses would be incurred, there are a number of factors beyond our and Blattner’s control that could affect the total amount or the timing of their integration expenses. Many of the expenses that will be incurred, by their nature, are difficult to estimate accurately at the present time. The overall expenses in connection with the acquisition are expected to be significant, although the aggregate amount and timing of such charges are uncertain at present.

**Item 2.**Unregistered Sales of Equity Securities and Use of Proceeds.

Unregistered Sales of Equity Securities

On July 30, 2021, we completed an acquisition in which a portion of the consideration consisted of the unregistered issuance of shares of our common stock. The aggregate consideration paid at closing in the acquisition included 32,822 shares of our common stock, which had a fair value of $2.5 million as of the acquisition date. Additionally, subsequent to September 30, 2021, we completed two acquisitions, on October 1, 2021 and October 13, 2021, in which a portion of the consideration for each acquisition consisted of the unregistered issuance of shares of our common stock. The aggregate consideration paid at closing in these acquisitions included 3,369,703 shares of our common stock.

For additional information about these acquisitions, see Note 4 of the Notes to Condensed Consolidated Financial Statements in Item 1. Financial Statements of Part I of this Quarterly Report. The issuance of shares of our common stock in connection with these acquisitions were not registered under the Securities Act in reliance upon the exemption from registration provided by Section 4(a)(2) of the Securities Act, which exempts transactions by an issuer not involving any public offering, and Rule 506 of Regulation D promulgated by the SEC under that section. These securities may not be offered or sold in the United States absent registration or an applicable exemption from the registration requirement.

Issuer Purchases of Equity Securities During the Third Quarter of 2021

The following table contains information about our purchases of equity securities during the three months ended September 30, 2021.

(1)Includes shares repurchased as of the trade date of such repurchases. On August 6, 2020, we issued a press release announcing that our Board of Directors approved a stock repurchase program that authorizes us to purchase, from time to time through June 30, 2023, up to $500 million of our outstanding common stock. Repurchases under this program can be made in open market and privately negotiated transactions, at our discretion, based on market and business conditions, applicable contractual and legal requirements and other factors. The program does not obligate us to acquire any specific amount of common stock and may be modified or terminated by our Board of Directors at any time at its sole discretion and without notice.

(2)Includes shares purchased from employees to satisfy tax withholding obligations in connection with the vesting of restricted stock unit and performance stock unit awards or the settlement of previously vested but deferred restricted stock unit and performance stock unit awards.

Item 3. Defaults Upon Senior Securities.

None.

Item 4. Mine Safety Disclosures.

Not applicable.