Acquisition-related contingent consideration and other liabilities is composed of Earn-outs, which represent the estimated fair value of future amounts payable for businesses, including for mandatorily redeemable non-controlling interests, that are contingent upon the acquired business achieving certain levels of earnings in the future. As of December 31, 2021 and 2020, the estimated fair value of the Company’s Earn-out liabilities totaled $160.2 million and $135.2 million, respectively, of which $13.9 million and $18.8 million, respectively, related to mandatorily redeemable non-controlling interests. Earn-out liabilities included within other current liabilities totaled approximately $38.8 million and $48.1 million as of December 31, 2021 and 2020, respectively. The fair values of the Company’s Earn-out liabilities are estimated using income approaches such as discounted cash flows or option pricing models, both of which incorporate significant inputs not observable in the market (Level 3 inputs), including management’s estimates and entity-specific assumptions, and are evaluated on an ongoing basis. Key assumptions include the discount rate, which, as of December 31, 2021, ranged from 12.0% to 17.9%, with a weighted average rate of 13.2% based on the relative fair value of each instrument, and probability-weighted projections of earnings before interest, taxes, depreciation and amortization (“EBITDA”). Significant changes in any of

these assumptions could result in significantly higher or lower potential Earn-out liabilities. The ultimate payment amounts for the Company’s Earn-out liabilities will be determined based on the actual results achieved by the acquired businesses. As of December 31, 2021, the range of potential undiscounted Earn-out liabilities was estimated to be between $38 million and $258 million; however, there is no maximum payment amount.

Earn-out activity consists primarily of additions from new business combinations; changes in the expected fair value of future payment obligations; and payments. For the years ended December 31, 2021, 2020 and 2019, additions to acquisition-related contingent consideration and other liabilities from new business combinations totaled approximately $101.6 million, $7.2 million and $45.2 million, respectively. There were no measurement period adjustments for the year ended December 31, 2021. Measurement period adjustments in 2020 totaled an increase of approximately $2.1 million and related to businesses in the Company’s Communications segment, and in 2019, totaled a decrease of approximately $6.1 million and related to businesses in the Company’s Oil and Gas and Communications segments. For the year ended December 31, 2021, fair value adjustments across multiple segments totaled a net decrease of approximately $29.5 million, including a $2.8 million decrease related to mandatorily redeemable non-controlling interests. For the year ended December 31, 2020, fair value adjustments across multiple segments totaled a net increase of approximately $3.1 million, including a $1.0 million increase related to mandatorily redeemable non-controlling interests, and for the year ended December 31, 2019, fair value adjustments totaled a net increase of approximately $51.0 million, and related primarily to Earn-outs for businesses in the Company’s Oil and Gas and Communications segments. Earn-out payments totaled $47.0 million, $50.4 million and $35.0 million for the years ended December 31, 2021, 2020 and 2019, respectively.

The Company’s equity investments as of December 31, 2021 include: (i) the Company’s 33% equity interests in Trans-Pecos Pipeline, LLC (“TPP”) and Comanche Trail Pipeline, LLC (“CTP,” and together with TPP, the “Waha JVs”); (ii) a 15% equity interest in Cross Country Infrastructure Services, Inc. (“CCI”); (iii) the Company’s 50% equity interests in each of FM Technology Holdings, LLC, FM USA Holdings, LLC and All Communications Solutions Holdings, LLC, collectively “FM Tech”; (iv) the Company’s equity interests in American Virtual Cloud Technologies, Inc., or “AVCT”; (v) the Company’s interests in certain proportionately consolidated non-controlled contractual joint ventures; and (vi) certain other equity investments.

As of December 31, 2021 and 2020, the aggregate carrying value of the Company’s equity investments, including equity investments measured on an adjusted cost basis, totaled approximately $267 million and $220 million, respectively. As of December 31, 2021 and 2020, equity investments measured on an adjusted cost basis, including the Company’s $15 million investment in CCI, totaled approximately $20 million and $17 million, respectively. There were no impairments of these investments in any of the years then ended.

The Waha JVs. The Waha JVs own and operate certain pipeline infrastructure that transports natural gas to the Mexican border for export. The Company’s investments in the Waha JVs are accounted for as equity method investments. Equity in earnings related to the Company’s proportionate share of income from the Waha JVs, which is included within the Company’s Other segment, totaled approximately $35.3 million, $31.3 million and $27.3 million for the years ended December 31, 2021, 2020 and 2019, respectively. Distributions of earnings from the Waha JVs, which are included within operating cash flows, totaled $7.7 million, $12.0 million and $9.1 million for the years ended December 31, 2021, 2020 and 2019, respectively. Cumulative undistributed earnings from the Waha JVs, which represents cumulative equity in earnings for the Waha JVs less distributions of earnings, totaled $94.8 million as of December 31, 2021. The Company’s net investment in the Waha JVs, which differs from its proportionate share of the net assets of the Waha JVs due primarily to equity method goodwill associated with capitalized investment costs, totaled approximately $216 million and $175 million as of December 31, 2021 and 2020, respectively.

The Waha JVs are party to separate non-recourse financing facilities, each of which are secured by pledges of the equity interests in the respective entities, as well as a first lien security interest over virtually all of their assets. The Waha JVs are also party to certain interest rate swaps (the “Waha JV swaps”), which are accounted for as qualifying cash flow hedges. The Company reflects its proportionate share of any unrealized fair market value gains or losses from fluctuations in interest rates associated with these swaps within other comprehensive income or loss, as appropriate. For the year ended December 31, 2021, the Company’s proportionate share of unrecognized unrealized activity on the Waha JV swaps totaled gains of approximately $18.2 million, or $13.8 million, net of tax, and for the years ended December 31, 2020 and 2019, totaled losses of approximately $24.4 million and $19.9 million, or $18.5 million or $15.0 million, net of tax, respectively.

Other Investments. As of December 31, 2021, the Company’s investments in AVCT, which are included within other current assets in the Company’s consolidated financial statements, include (i) shares of AVCT common stock, which are equity securities and (ii) warrants for the purchase of AVCT common stock, which are derivative financial instruments. Previously, the Company’s investment in AVCT included debentures that were convertible into shares of AVCT common stock, which were available-for-sale securities. In the third quarter of 2021, the Company’s investment in AVCT convertible debentures was automatically converted into shares of AVCT common stock. As of December 31, 2021 and 2020, the Company’s ownership interest in AVCT’s common stock, including from the converted debentures, totaled approximately 3% and 9%, respectively, and its aggregate ownership interest, assuming the exercise and, as of December 31, 2020, the conversion of all legally exercisable warrants and convertible debentures into AVCT common stock, totaled approximately 6% and 21%, respectively. José R. Mas, MasTec’s Chief Executive Officer, was a director of AVCT through the end of March 2020. The issued shares and those underlying the derivative instruments are salable at various times subject to various contractual and securities law restrictions. The Company does not have the ability to exert significant influence over the operating or financial policies of AVCT.

As of December 31, 2021 and 2020, the aggregate fair value of the Company’s investments in AVCT approximated $8 million and $17 million, respectively, with an aggregate cost approximating $6 million and $5 million, respectively. Unrealized fair value measurement activity related to the AVCT securities recorded within other income or expense, net, totaled losses of approximately $8.5 million for the year ended December 31, 2021, and totaled gains of approximately $10.1 million for the year ended December 31, 2020. The fair value of the AVCT shares is determined based on the market price of identical securities, which is a Level 1 input, beginning as of the second quarter of 2021. Previously, the fair value of the shares was adjusted for certain restrictions on sale, a Level 3 input, which restrictions expired in April 2021. In the third quarter of 2021, in conjunction with the automatic conversion of the AVCT convertible debentures into shares of AVCT common stock, the Company reclassified a gain of $0.7 million from other comprehensive income to other income, net. Prior to the conversion of the AVCT convertible debentures in the third

quarter of 2021, unrealized fair value measurement activity related to the AVCT convertible debentures recognized within other comprehensive income totaled losses of approximately $1.1 million, or $0.8 million, net of tax, respectively, for the year ended December 31, 2021, and totaled gains of approximately $1.8 million, or $1.4 million, net of tax, respectively, for the year ended December 31, 2020. The fair value of the AVCT convertible debentures was determined based on Level 3 inputs.

During the first quarter of 2021, MasTec committed to fund up to $2.5 million for a 75% equity interest in Confluence Networks, LLC (“Confluence”), an undersea fiber-optic communications systems developer and VIE, of which $1.7 million was funded during 2021. Equity in losses related to the Company’s proportionate share of income from this investment totaled $0.7 million for the year ended December 31, 2021. As of December 31, 2021, MasTec had less than a majority of the members on the board and determined that it did not have a controlling financial interest. The Company has the ability to exert significant influence over the VIE, and, as a result, the Company’s investment in Confluence was accounted for as an equity method investment as of December 31, 2021.

The Company has equity interests in certain telecommunications entities that are accounted for as equity method investments, for which the Company had an aggregate investment of $20 million and $19 million as of December 31, 2021 and 2020, respectively, including $17 million and $16 million, respectively, for FM Tech. The investment in FM Tech provides for additional funding upon the resolution of certain contingencies, of which $2 million was paid in 2021. The fair value of the remaining contingent payments for FM Tech, which are included within other current liabilities, was estimated to be $3 million and $5 million as of December 31, 2021 and 2020, respectively. As of December 31, 2021, the contingent payment could range up to $7 million. For the year ended December 31, 2021, the Company made equity contributions related to its investments in telecommunications entities totaling approximately $2 million, and for the years ended December 31, 2020 and 2019, made no equity contributions. Equity in losses, net, related to the Company’s proportionate share of income from these telecommunications entities totaled approximately $0.7 million and $1.5 million for the years ended December 31, 2021 and 2020, respectively, and for the year ended December 31, 2019, was de minimis. The difference between the carrying amount of these investments and the Company’s underlying equity in the net assets of the respective entities relates primarily to equity method goodwill associated with assembled workforce for each of these entities.

Certain of these entities provide services to MasTec. Expense recognized in connection with services provided by these entities for the years ended December 31, 2021, 2020 and 2019 totaled $9.9 million, $11.5 million and $7.0 million, respectively. As of December 31, 2021 and 2020, related amounts payable to these entities totaled $0.3 million and $0.2 million, respectively. In addition, the Company has an employee leasing arrangement with one of these entities. Charges to this entity were de minimis for year ended December 31, 2021, and totaled $0.4 million for the year ended December 31, 2020. As of December 31, 2021 and 2020, related amounts receivable totaled $0.7 million and $0.4 million, respectively. Amounts advanced to these entities for the year ended December 31, 2021 totaled $0.2 million, which amount was outstanding as of December 31, 2021.

As of both December 31, 2021 and 2020, the gross carrying amount of the Company’s 4.50% senior notes due August 15, 2028 (the “4.50% Senior Notes”) totaled $600.0 million, and their estimated fair value, based on an exit price approach using Level 1 inputs, totaled $619.5 million and $625.5 million, respectively. See Note 7 - Debt for information related to the Company’s debt instruments.