For the quarterly period ended March 31, 2017

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes x No o

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232,405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes x No o

Indicate by check mark whether the registrant is a shell company (as defined by Rule 12b-2 of the Act). Yes o No x

As of April 27, 2017, there were 150,496,403 shares of the registrant’s common stock, par value $0.0001 per share, issued and outstanding.

(In thousands, Unaudited)             See accompanying notes to condensed consolidated financial statements.

Nature of Business  Clean Energy Fuels Corp., together with its majority and wholly owned subsidiaries (hereinafter collectively referred to as the "Company," unless the context or the use of the term indicates or requires otherwise) is engaged in the business of selling natural gas as an alternative fuel for vehicle fleets and related natural gas fueling solutions to its customers, primarily in the United States and Canada.

Basis of Presentation  The accompanying interim unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries, and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to state fairly the Company’s financial position, results of operations, comprehensive income and cash flows as of and for the three months ended March 31, 2016 and 2017. All intercompany accounts and transactions have been eliminated in consolidation. The three month periods ended March 31, 2016 and 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 or for any other interim period or for any future year.

Certain information and disclosures normally included in the notes to the financial statements have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”), but the resultant disclosures contained herein are in accordance with accounting principles generally accepted in the United States of America (“US GAAP”) as they apply to interim reporting. The condensed consolidated financial statements should be read in conjunction with the consolidated financial statements as of and for the year ended December 31, 2016 that are included in the Company’s Annual Report on Form 10-K filed with the SEC on March 7, 2017.

Reclassifications Certain prior period line items in the condensed consolidated statements of operations and condensed consolidated statements of cash flows have been reclassified to conform to the classifications used to prepare the condensed consolidated financial statements for the period ended March 31, 2017. These reclassifications had no material impact on the Company’s financial position, results of operations, or cash flows as previously reported.

Use of Estimates  The preparation of condensed consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates and may result in material effects on the Company’s operating results and financial position.

On February 27, 2017, Clean Energy Renewable Fuels ("Renewables"), a subsidiary of the Company, entered into an asset purchase agreement (the “APA”) with BP Products North America, Inc. (“BP”), pursuant to which Renewables agreed to sell to BP certain assets relating to its RNG production business (the “Asset Sale”), consisting of Renewables’ two existing RNG production facilities, Renewables’ interest in the RNG Ventures and Renewables’ third-party RNG supply contracts (the “Assets”). The Asset Sale was completed on March 31, 2017 for a sale price of $155,511, plus BP assumed the obligations under the Canton Bonds (as defined in Note 12), which totaled $8,820 as of March 31, 2017.

On March 31, 2017 BP paid Renewables $30,000 in cash and delivered to Renewables a promissory note with a principal amount of $123,487 (the promissory note was paid in full on April 3, 2017). In addition, BP is obligated to pay Renewables $2,024 related to the determination of certain post-closing adjustments. As defined in the APA, the valuation date of the Asset Sale was January 1, 2017, and as such the APA included certain adjustments to the purchase price to reflect a determination of the amount

In addition, under the APA, BP is required, following the closing of the Asset Sale, to pay Renewables up to an additional $25,000 in cash over a five-year period if certain performance criteria relating to the Assets are met.

The Company incurred $3,695 in transaction fees in connection with the Asset Sale, and subsequent to March 31, 2017, the Company paid $8,605 in cash and issued 770,269 shares valued at $1,964, of the Company's common stock to holders of options to purchase membership units in Renewables. The net proceeds from the Asset Sale were $143,211. The BP Note delivered to Renewables in connection with the Asset Sale was excluded from the Company's condensed consolidated statement of cash flows as it is a non-cash investing activity.

The Asset Sale resulted in a total gain of $70,648 that was recorded in gain from sale of certain assets of subsidiary in the Company's condensed consolidated statement of operations for the three months ended March 31, 2017. Included in the determination of the total gain is goodwill of $26,576 that was allocated to the disposed assets based on the relative fair values of the assets disposed and the portion of the reporting unit that was retained.

Note 3—Cash and Cash Equivalents

At times, such investments may be in excess of the Federal Deposit Insurance Corporation (“FDIC”), Canadian Deposit Insurance Corporation (“CDIC”) and other foreign insurance limits. Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash deposits. The amounts in excess of FDIC, CDIC and other foreign insurance limits were approximately $34,439 and $44,963 at December 31, 2016 and March 31, 2017, respectively.

Note 4—Restricted Cash

The Company classifies restricted cash as short-term and a current asset if the cash is expected to be used in operations within a year or to acquire a current asset. Otherwise, the restricted cash is classified as long-term. Short-term restricted cash at December 31, 2016 and March 31, 2017 consisted of the following:

Note 5—Investments

cost basis and adverse conditions related specifically to the security, including any changes to the credit rating of the security. As of March 31, 2017, the Company believes its carrying values for its available-for-sale securities are properly recorded.    

Short-term investments as of December 31, 2016 consisted of the following:

Short-term investments as of March 31, 2017 consisted of the following:

Note 6—Fair Value Measurements

As of March 31, 2017, the Company's financial instruments consisted of available-for-sale securities, liability-classified warrants, and debt instruments. The Company’s available-for-sale securities are classified within Level 2 because they are valued using the most recent quoted prices for identical assets in markets that are not active and quoted prices for similar assets in active markets. The liability-classified warrants are classified within Level 3 because the Company uses the Black-Scholes option pricing model to estimate the fair value based on inputs that are not observable in any market. The fair values of the Company's debt instruments approximated their carrying values as of December 31, 2016 and March 31, 2017. See Note 12 for further information about the Company's debt instruments. There were no transfers of assets between Level 1, Level 2, or Level 3 of the fair value hierarchy as of December 31, 2016 and March 31, 2017, respectively.

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2016 and March 31, 2017, respectively:

(1) Included in short-term investments in the condensed consolidated balance sheets. See Note 5 for further information.

No impairments of long-lived assets measured at fair value on a non-recurring basis have been incurred during the three months ended March 31, 2016 and 2017. The Company’s use of these non-financial assets does not differ from their highest and best use as determined from the perspective of a market participant.

Note 7—Other Receivables

Other receivables as of December 31, 2016 and March 31, 2017 consisted of the following:

Note 8—Inventory

Inventories as of December 31, 2016 and March 31, 2017 consisted of the following:

Note 9—Land, Property and Equipment

Land, property and equipment as of December 31, 2016 and March 31, 2017 consisted of the following:

(1) The RNG plants were sold in connection with the Asset Sale (See Note 2 for further information).

Included in land, property and equipment are capitalized software costs of $25,728 and $25,791 as of December 31, 2016 and March 31, 2017, respectively. The accumulated amortization of the capitalized software costs is $17,237 and $18,109 as of December 31, 2016 and March 31, 2017, respectively.

The Company recorded amortization expense related to the capitalized software costs of $938 and $872 during the three months ended March 31, 2016 and 2017, respectively.

As of March 31, 2016 and 2017, $6,077 and $2,884, respectively, are included in accounts payable and accrued liabilities balances, which amounts are related to purchases of property and equipment. These amounts are excluded from the condensed consolidated statements of cash flows as they are non-cash investing activities.

Note 10— Investments in Other Entities and Noncontrolling Interest in a Subsidiary

In November 2016, Renewables entered into agreements to form joint ventures with Aria Energy Operating LLC ("Aria"), a developer of RNG production facilities, to develop RNG production facilities at a Republic Services landfill in Oklahoma City, Oklahoma and an Advanced Disposal landfill near Atlanta, Georgia. These joint ventures are referred to as the "RNG Ventures." Renewables' interest in the RNG Ventures was transferred to BP upon completion of the Asset Sale; however, Renewables retained the right to purchase 100% of the RNG that will be produced by the production facilities to be developed by the RNG Ventures for the vehicle fuels market.  The Company accounted for its interest in the RNG Ventures using the equity method of accounting as the Company had the ability to exercise significant influence over these operations. The Company had an investment balance of $833 and $0 in the RNG Ventures as of December 31, 2016 and March 31, 2017, respectively. See Note 2 for further information.

On September 16, 2014, the Company formed a joint venture with Mansfield Ventures LLC (“Mansfield”) called Mansfield Clean Energy Partners LLC (“MCEP”), which is designed to provide natural gas fueling solutions to bulk fuel haulers in the United States. The Company and Mansfield each have a 50% ownership interest in MCEP. The Company accounts for its interest in MCEP using the equity method of accounting, as the Company has the ability to exercise significant influence over MCEP’s operations. The Company recorded a loss from this investment of $74 and $36 for the three months ended March 31,

2016 and 2017, respectively. Additionally, on June 28, 2016, the Company received a return of capital of $3,031 with no change in ownership interest. The Company has an investment balance of $1,642 and $1,606 at December 31, 2016 and March 31, 2017, respectively.

On October 14, 2014, the Company entered into a Common Unit Purchase Agreement (“UPA”) with NG Advantage, LLC (“NG Advantage”) for a 53.3% controlling interest in NG Advantage. NG Advantage is engaged in the business of transporting CNG in high-capacity trailers to industrial and institutional energy users, such as hospitals, food processors, manufacturers and paper mills that do not have direct access to natural gas pipelines. The Company viewed the acquisition as a strategic investment in the expansion of the Company’s initiative to deliver natural gas to industrial and institutional energy users. The results of NG Advantage’s operations have been included in the Company’s consolidated financial statements since October 14, 2014.

The Company recorded a loss from the noncontrolling interest in NG Advantage of $299 and $335 for the three months ended March 31, 2016 and 2017, respectively. The noncontrolling interest was $24,822 and $24,487 as of December 31, 2016 and March 31, 2017, respectively.

Note 11—Accrued Liabilities

Accrued liabilities as of December 31, 2016 and March 31, 2017 consisted of the following:

(2) Accrued liabilities as of March 31, 2017 include the accrual of transaction fees and awards of shares of the Company's common stock related to the Asset Sale (See Note 2 for further information).

Note 12—Debt

Debt and capital lease obligations as of December 31, 2016 and March 31, 2017 consisted of the following and are further discussed below:

(1) Includes $65,000 and $40,000 in principal amount held by T. Boone Pickens ("Mr. Pickens"), as of December 31, 2016 and March 31, 2017, respectively, which is classified as “Long-term debt, related party” on the condensed consolidated balance sheet. See the description below for additional information.

7.5% Notes

On July 11, 2011, the Company entered into a loan agreement (the “CHK Agreement”) with Chesapeake NG Ventures Corporation (“Chesapeake”), an indirect wholly owned subsidiary of Chesapeake Energy Corporation, whereby Chesapeake agreed to purchase from the Company up to $150,000 of debt securities pursuant to the issuance of three convertible promissory notes over a three-year period, each having a principal amount of $50,000 (each a “CHK Note” and collectively the “CHK Notes” and, together with the CHK Agreement and other transaction documents, the “CHK Loan Documents”). The first CHK Note was issued on July 11, 2011 and the second CHK Note was issued on July 10, 2012.

On June 14, 2013 (the “Transfer Date”), Mr. Pickens and Green Energy Investment Holdings, LLC ("GEIH"), an affiliate of Leonard Green & Partners, L.P. (collectively, the “Buyers”), and Chesapeake entered into a note purchase agreement (“Note Purchase Agreement”) pursuant to which Chesapeake sold the outstanding CHK Notes (the “Sale”) to the Buyers. Chesapeake assigned to the Buyers all of its right, title and interest under the CHK Loan Documents (the “Assignment”), and each Buyer severally assumed all of the obligations of Chesapeake under the CHK Loan Documents arising after the Sale and the Assignment including, without limitation, the obligation to advance an additional $50,000 to the Company in June 2013 (the “Assumption”). The Company also entered into the Note Purchase Agreement for the purpose of consenting to the Sale, the Assignment and the Assumption.

Contemporaneously with the execution of the Note Purchase Agreement, the Company entered into a loan agreement with each Buyer (collectively, the “Amended Agreements”). The Amended Agreements have the same terms as the CHK Agreement, other than changes to reflect the new holders of the CHK Notes. Immediately following execution of the Amended Agreements, the Buyers delivered $50,000 to the Company in satisfaction of the funding requirement they had assumed from Chesapeake (the “2013 Advance”). In addition, the Company canceled the existing CHK Notes and issued replacement notes, and the Company also issued notes to the Buyers in exchange for the 2013 Advance (the replacement notes and the notes issued in exchange for the 2013 Advance are referred to herein as the “7.5% Notes”).

The 7.5% Notes have the same terms as the original CHK Notes, other than changes to reflect their different holders. They bear interest at the rate of 7.5% per annum and are convertible at the option of the holder into shares of the Company’s common stock at a conversion price of $15.80 per share (the “7.5% Notes Conversion Price”). Upon written notice to the Company, each holder of a 7.5% Note has the right to exchange all or any portion of the principal and accrued and unpaid interest under its 7.5% Notes for shares of the Company’s common stock at the 7.5% Notes Conversion Price.

Additionally, subject to certain restrictions, the Company can force conversion of each 7.5% Note into shares of its common stock if, following the second anniversary of the issuance date of a 7.5% Note, such shares trade at a 40% premium to the 7.5% Notes Conversion Price for at least 20 trading days in any consecutive 30 trading day period.

The entire principal balance of each 7.5% Note is due and payable seven years following its issuance and the Company may repay each 7.5% Note at maturity in shares of its common stock (with a value determined by the per share volume weighted-average price for the 20 trading days prior to the maturity date) or cash. All of the shares issuable upon conversion of the 7.5% Notes have been registered for resale by their holders pursuant to a registration statement that has been filed with and declared effective by the Securities and Exchange Commission.

The Amended Agreements provide for customary events of default which, if any of them occurs, would permit or require the principal of, and accrued interest on, the 7.5% Notes to become, or to be declared, due and payable. No events of default under the 7.5% Notes had occurred as of March 31, 2017.

On August 27, 2013, GEIH transferred $5,000 in principal amount of its 7.5% Notes to certain third parties.

On February 9, 2017, the Company purchased from Mr. Pickens, his 7.5% Note due July 2018 having an outstanding principal amount of $25,000 held by Mr. Pickens for a cash purchase price of $21,750. The Company's repurchase of this 7.5% Note resulted in a total gain of $3,191 for the three months ended March 31, 2017.

On February 21, 2017, GEIH transferred an additional $11,800 in principal amount of its 7.5% Notes to a third party.

As a result of the foregoing transactions, as of March 31, 2017, (i) Mr. Pickens held 7.5% Notes in the aggregate principal amount of $40,000, (ii) GEIH held 7.5% Notes in the aggregate principal amount of $68,200, and (iii) other third parties held 7.5% Notes in the aggregate principal amount of $16,800.

5.25% Notes

In September 2013, the Company completed a private offering of $250,000 in principal amount of 5.25% Convertible Senior Notes due 2018 (the “5.25% Notes”) and entered into an indenture governing the 5.25% Notes (the “Indenture”).

The net proceeds from the sale of the 5.25% Notes after the payment of certain debt issuance costs of $7,805 were $242,195. The Company has used the net proceeds from the sale of the 5.25% Notes to fund capital expenditures and for general corporate purposes. The 5.25% Notes bear interest at a rate of 5.25% per annum, payable semi-annually in arrears on October 1 and April 1 of each year, beginning on April 1, 2014. The 5.25% Notes will mature on October 1, 2018, unless purchased, redeemed or converted prior to such date in accordance with their terms and the terms of the Indenture.

Holders may convert their 5.25% Notes, at their option, at any time prior to the close of business on the business day immediately preceding the maturity date of the 5.25% Notes. Upon conversion, the Company will deliver a number of shares of its common stock, per $1 principal amount of 5.25% Notes, equal to the conversion rate then in effect (together with a cash payment in lieu of any fractional shares). The initial conversion rate for the 5.25% Notes is 64.1026 shares of the Company’s common stock per $1 principal amount of 5.25% Notes (which is equivalent to an initial conversion price of approximately $15.60 per share of the Company’s common stock). The conversion rate is subject to adjustment upon the occurrence of certain specified events as described in the Indenture. Upon the occurrence of certain corporate events prior to the maturity date of the 5.25% Notes, the Company will, in certain circumstances, in addition to delivering the number of shares of the Company’s common stock deliverable upon conversion of the 5.25% Notes based on the conversion rate then in effect (together with a cash payment in lieu of any fractional shares), pay holders that convert their 5.25% Notes a cash make-whole payment in an amount as described in

The Company may not redeem the 5.25% Notes prior to October 5, 2016. On or after October 5, 2016, the Company may, at its option, redeem for cash all or any portion of the 5.25% Notes if the closing sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which notice of redemption is provided, exceeds 160% of the conversion price on each applicable trading day. In the event of the Company’s redemption of the 5.25% Notes, the redemption price will equal 100% of the principal amount of the 5.25% Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for in the 5.25% Notes.

If the Company undergoes a fundamental change (as defined in the Indenture) prior to the maturity date of the 5.25% Notes, subject to certain conditions as described in the Indenture, holders may require the Company to purchase, for cash, all or any portion of their 5.25% Notes at a repurchase price equal to 100% of the principal amount of the 5.25% Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change purchase date.

The Indenture contains customary events of default with customary cure periods, including, without limitation, failure to make required payments or deliveries of shares of the Company’s common stock when due under the Indenture, failure to comply with certain covenants under the Indenture, failure to pay when due or acceleration of certain other indebtedness of the Company or certain of its subsidiaries, and certain events of bankruptcy and insolvency of the Company or certain of its subsidiaries. The occurrence of an event of default under the Indenture will allow either the trustee or the holders of at least 25% in principal amount of the then-outstanding 5.25% Notes to accelerate, or upon an event of default arising from certain events of bankruptcy or insolvency of the Company, will automatically cause the acceleration of, all amounts due under the 5.25% Notes. No events of default under the 5.25% Notes had occurred as of March 31, 2017.

The 5.25% Notes are senior unsecured obligations of the Company and rank senior in right of payment to the Company’s future indebtedness that is expressly subordinated in right of payment to the 5.25% Notes; equal in right of payment to the Company’s unsecured indebtedness that is not so subordinated; effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness (including trade payables) of the Company’s subsidiaries.

During the year ended December 31, 2016, the Company paid an aggregate of $84,344 in cash to repurchase and retire $114,550 in aggregate principal amount of the 5.25% Notes, together with $1,546 in accrued and unpaid interest thereon. Additionally, pursuant to a privately negotiated exchange agreement with certain holders of the 5.25% Notes, on May 4, 2016, the Company issued 6,265,829 shares of its common stock in exchange for an aggregate principal amount of $25,000 of 5.25% Notes held by such holders and accrued and unpaid interest thereon. The value of the shares of the Company's common stock issued to the holders of the 5.25% Notes in the exchange has been excluded from the Company's condensed consolidated statements of cash flows as it is a non-cash financing activity. The Company's repurchase and exchange of 5.25% Notes for the year ended December 31, 2016 resulted in a total gain of $35,239 recorded during the period. All repurchased and exchanged 5.25% Notes have been surrendered to the trustee for such notes and canceled in full and the Company has no further obligations under such notes.

On February 29, 2016, the Company entered into a Loan and Security Agreement (“LSA”) with PlainsCapital Bank (“Plains”), pursuant to which Plains agreed to lend the Company up to $50,000 on a revolving basis from time to time for a term of one year (the “Credit Facility”). All amounts advanced under the Credit Facility were due and payable on February 28, 2017. Simultaneously, the Company drew $50,000 under this Credit Facility, which the Company repaid in full on August 31, 2016. On October 31, 2016 the LSA was amended solely to extend the Credit Facility's maturity date from February 28, 2017 to September 30, 2018. On December 22, 2016, the Company drew $23,500 under the Credit Facility, which the Company repaid in full on March 31, 2017. As a result, the Company has no amounts outstanding under the Credit Facility as of March 31, 2017.

The Credit Facility is evidenced by a promissory note the Company issued on February 29, 2016 in favor of Plains (the “Plains Note”). Interest on the Plains Note is payable monthly and accrues at a rate equal to the greater of (i) the then-current LIBOR rate plus 2.30% or (ii) 2.70%. As collateral security for the prompt payment in full when due of the Company's obligations to Plains under the LSA and the Plains Note, the Company pledged to and granted Plains a security interest in all of its right, title

and interest in the cash and corporate and municipal bonds rated AAA, AA or A by Standard & Poor’s Rating Services that the Company holds in an account at Plains. In connection with such pledge and security interest granted under the Credit Facility, on February 29, 2016, the Company entered into a Pledged Account Agreement with Plains and PlainsCapital Bank - Wealth Management and Trust (the “Pledge Agreement” and collectively with the LSA and the Plains Note, the “Plains Loan Documents”).The Plains Loan Documents include certain covenants of the Company and also provide for customary events of default, which, if any of them occurs, would permit or require, among other things, the principal of, and accrued interest on, the Credit Facility to become, or to be declared, due and payable. Events of default under the Plains Loan Documents include, among others, the occurrence of certain bankruptcy events, the failure to make payments when due under the Plains Note and the transfer or disposal of the collateral under the LSA. No events of default under the Plains Loan Documents had occurred as of March 31, 2017.

On March 19, 2014, Canton Renewables, LLC (“Canton”), a former subsidiary of the Company, completed the issuance of Solid Waste Facility Limited Obligation Revenue Bonds (Canton Renewables, LLC — Sauk Trail Hills Project) Series 2014 in the aggregate principal amount of $12,400 (the “Canton Bonds”).

On March 31, 2017, Canton was sold to BP in the Asset Sale (see Note 2). As a result, the Canton Bonds became the obligation of BP as of such date.

On May 12, 2016 and January 24, 2017, respectively, NG Advantage entered into a loan and security agreement (“LSA”) with Commerce Bank & Trust Company (“Commerce”), pursuant to which Commerce agreed to lend NG Advantage $6,300 and $6,150, respectively. The proceeds were primarily used to fund the purchases of CNG trailers and equipment. Interest and principal for both loans are payable monthly in eighty-four equal monthly installments at an annual rate of 4.41% and 5.0%, respectively. As collateral security for the prompt payment in full when due of the NG Advantage's obligations to Commerce under the LSA, NG Advantage pledged to and granted Commerce a security interest in all of its right, title and interest in the CNG trailers and equipment.

On November 30, 2016, NG Advantage entered into a LSA with Wintrust Commercial Finance (“Wintrust”), pursuant to which Wintrust agreed to lend NG Advantage $4,695. The proceeds were primarily used to fund the purchases of CNG trailers and equipment. Interest and principal is payable monthly in seventy-two equal monthly installments at an annual rate of 5.17%. As collateral security for the prompt payment in full when due of the NG Advantage's obligations to Wintrust under the LSA and the Plains Note, NG Advantage pledged to and granted Wintrust a security interest in all of its right, title and interest in the CNG trailers and equipment.

NG Advantage has other debt for trailers and equipment due at various dates through 2021 bearing interest at rates up to 6.01%, with weighted average interest rates of 5.51% and 5.46%, and outstanding principal balance of $2,598 and $2,418 as of December 31, 2016 and March 31, 2017, respectively.

The Company has other debt due at various dates through 2023 bearing interest at rates up to 5.02% with weighted average interest rates of 5.72% and 4.66% as of December 31, 2016 and March 31, 2017, respectively.

Note 13—Net Income Per Share

At-The-Market Offering Program On November 11, 2015, the Company entered into an equity distribution agreement with Citigroup Global Markets Inc. (“Citigroup”), as sales agent and/or principal, pursuant to which the Company may issue and sell, from time to time, through or to Citigroup shares of the Company's common stock having an aggregate offering price of up to $75,000 in an “at-the-market” offering program (the “ATM Program”). On September 9, 2016, the Company entered into an amended and restated equity distribution agreement with Citigroup, which amends, restates, and replaces the original equity distribution agreement in its entirety, for the primary purpose of increasing from $75,000 to $110,000 the aggregate offering price of shares of common stock available for issuance and sale in the ATM Program. On December 21, 2016, the Company entered into a second amended and restated equity distribution agreement with Citigroup, for the primary purpose of increasing from $110,000 to $200,000 the aggregate offering price of shares of common stock available for issuance and sale in the ATM program.

Note 14—Stock-Based Compensation

At March 31, 2017, there was $11,330 of total unrecognized compensation costs related to non-vested shares subject to outstanding stock options and restricted stock units, which is expected to be expensed over a weighted-average period of approximately 2.05 years.

Note 15—Income Taxes

The Company’s income tax benefit (expense) for the three months ended March 31, 2016 and 2017 was $(381) and $2,263, respectively. Tax benefit (expense) for all periods was comprised of taxes due on the Company’s U.S. and foreign operations. The increase in the Company’s income tax benefit for the three months ended March 31, 2017 as compared to the three months ended March 31, 2016 was primarily due to a deferred tax benefit attributed to the reduction of goodwill that arose from the Asset Sale (see Note 2). The effective tax rates for the three months ended March 31, 2016 and 2017 are different from the federal statutory tax rate primarily as a result of losses for which no tax benefit has been recognized.

During the three months ended March 31, 2017, the Company also benefited from the utilization of federal and state net operating loss ("NOL") carryovers that offset all of the Company's federal and the majority of its state taxes. In addition to the decrease in its deferred tax liability of $2,493 attributed to the reduction in goodwill, the utilization of NOLs also resulted in a decrease in the Company's deferred tax assets attributed to NOLs by $29,768 and a corresponding decrease in the Company deferred tax asset valuation allowance.

The Company did not record a change in its liability for unrecognized tax benefits or penalties in the three months ended March 31, 2016 or 2017. The net interest incurred was immaterial for both the three months ended March 31, 2016 and 2017, respectively.

Note 16—Commitments and Contingencies

Environmental Matters    

Note 17—Alternative Fuels Excise Tax Credit

In December 2015, Congress passed the Consolidated Appropriations Act that included an alternative fuel tax credit which we refer to as "VETC." The credit was made retroactive to January 1, 2015 and extended through December 31, 2016, except that the alternative fuels fuel tax credit for LNG sold as a vehicle fuel in 2016 was changed to be based on the diesel gallon equivalent of LNG sold rather than the liquid gallon of LNG sold. As a result, the Company was eligible to receive a credit of $0.50 per gasoline gallon equivalent of CNG sold as a vehicle fuel in 2016 and $0.50 per diesel gallon equivalent of LNG sold in 2016.

VETC revenue for the three months ended March 31, 2016 was $6,381. VETC ceased to be available after it expired on December 31, 2016 and may not be available for any subsequent period.

Note 18—Recently Issued and Adopted Accounting Standards

In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-03, Accounting Changes and Error Corrections (Topic 250) and Investments - Equity Method and Joint Ventures (Topic 323): Amendments to SEC Paragraphs Pursuant to Staff Announcements at the September 22, 2016 and November 17, 2016 EITF Meetings. This ASU requires registrants to disclose the effect that ASU 2014-09 (Revenue from Contracts with Customers (Topic 606), ASU 2016-02 (Leases (Topic 842), and ASU 2016-13 (Financial Instruments--Credit Losses (Topic 326) will have on their financial statements when adopted in a future period. In cases where a registrant cannot reasonably estimate the impact of the adoption, additional qualitative disclosures should be considered to assist the reader in assessing the significance of the standard’s impact on its financial statements. This guidance was effective upon issuance and other than enhancements to the qualitative disclosures regarding the future adoption of the referenced ASUs above, adoption of this ASU is not expected to have any impact on the Company’s condensed consolidated financial statements.

In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory. Under the new standard, the selling (transferring) entity is required to recognize a current tax expense or benefit upon transfer of the asset. Similarly, the purchasing (receiving) entity is required to recognize a deferred tax asset or liability, as well as the related deferred tax benefit or expense, upon purchase or receipt of the asset. The Company early adopted the standard as of January 1, 2017. This election was implemented under the modified retrospective approach, resulting in a $302 increase in accumulated deficit representing the cumulative recognition of the income tax consequences of intra-entity transfers of assets other than inventory that occurred before the adoption date.

In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payments Accounting. The new standard was issued to simplify the accounting for share-based payment transactions, including income tax consequences, the classification of awards as either equity or liabilities, and the classification on the statement of cash flows. The Company adopted the standard as of January 1, 2017 and in connection with the adoption, the Company elected to recognize forfeitures when they occur. Previously, the Company estimated a forfeiture rate in accordance with prior guidance. This election was implemented under the modified retrospective approach with a cumulative effect of an increase in accumulated deficit of $194, net of tax. This adjustment represents the cumulative additional compensation expense that would have been amortized through the date of adoption had this accounting policy election been in place. This ASU also eliminates the requirement to defer recognition of an excess tax benefit until the benefit is realized through a reduction to taxes payable. As a result, the Company’s deferred tax asset relating to its net operating loss carryovers increased by $8,600 with a corresponding increase in the deferred tax asset valuation allowance. The Company will also adopt on a prospective basis (1) the classification of excess tax benefits as an operating activity in the condensed consolidated statements of cash flows and (2) the exclusion of the amount of excess tax benefits when applying the treasury stock method for the Company’s diluted earnings per share calculation. Neither of these adoptions had a material impact on the Company's cash flows or diluted earnings per share calculation for the period ended March 31, 2017. Additionally, the Company continues to (1) classify cash paid by the Company for directly withholding shares for tax withholding purposes as a financing activity in the condensed consolidated statements of cash flows and (2) withhold the statutory minimum taxes for participants in the Company’s stock-based compensation plans.

The following Management’s Discussion and Analysis of Financial Condition and Results of Operations (the “MD&A”) should be read together with the unaudited condensed consolidated financial statements and the related notes included in this report. For additional context with which to understand our financial condition and results of operations, refer to the MD&A for the fiscal year ended December 31, 2016 included in our Annual Report on Form 10-K for our fiscal year ended December 31, 2016, which was filed with the Securities and Exchange Commission (“SEC”) on March 7, 2017, as well as the audited consolidated financial statements and notes included therein (collectively, our “2016 10-K”). Unless the context indicates otherwise, all

We serve fleet vehicle operators in a variety of markets, including heavy-duty trucking, airports, refuse, public transit, government fleets, and industrial and institutional energy users. We believe these fleet markets will continue to present a growth opportunity for natural gas vehicle fuel for the foreseeable future. As of March 31, 2017, we serve nearly 1,000 fleet customers operating over 46,000 natural gas vehicles, and we own, operate or supply over 575 natural gas fueling stations in 42 states in the United States and four provinces in Canada.

In evaluating our operating performance, our management focuses primarily on: (1) the amount of CNG, LNG and RNG gasoline gallon equivalents delivered (which we define as (i) the volume of gasoline gallon equivalents we sell to our customers, plus (ii) the volume of gasoline gallon equivalents dispensed at facilities we do not own but where we provide O&M services on a per-gallon or fixed fee basis, plus (iii) our proportionate share of the gasoline gallon equivalents sold as CNG by our joint venture with Mansfield Ventures, LLC called Mansfield Clean Energy Partners, LLC (“MCEP”), plus (iv) our proportionate share (as applicable) of the gasoline gallon equivalents of RNG produced and sold as pipeline quality natural gas by the RNG production facilities we owned or operated), (2) our station construction cost of sales, (3) our gross margin (which we define as revenue minus cost of sales), and (4) net income (loss) attributable to us. The following tables, which should be read in conjunction with the condensed consolidated financial statements and notes included in this report and the consolidated financial statements and notes included in our 2016 Form 10-K, present our key operating data for the years ended December 31, 2014, 2015, and 2016 and for the three months ended March 31, 2016 and 2017: