*All derivative instruments were current at December 31, 2015.

Due to the volatility of commodity prices, the estimated fair value of our derivative instruments is subject to fluctuation from period to period, which could result in significant differences between the current estimated fair value and the ultimate settlement price. Additionally, Energen is at risk of economic loss based upon the creditworthiness of our counterparties. We were in a net gain position with six of our active counterparties and in a net loss position with the remaining four at March 31, 2016 . The largest counterparty net gain positions at March 31, 2016 , Morgan Stanley Capital Group Inc. and BP Corporation North America Inc., constituted approximately $11.3 million and $6.1 million , respectively, of Energen’s total gain on fair value of derivatives.

The following table details the effect of open and closed derivative commodity instruments not designated as hedging instruments on the income statement:

As of March 31, 2016, Energen had entered into the following transactions for the remainder of 2016 and subsequent years:

As of March 31, 2016 , the maximum term over which Energen has hedged exposures to the variability of cash flows is through December 31, 2017.

3. FAIR VALUE MEASUREMENTS

Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). In determining fair value, we use various valuation approaches and classify all assets and liabilities based on the lowest level of input that is significant to the fair value measurement. Observable inputs represent market data obtained from independent sources, whereas unobservable inputs reflect our own considerations about the assumptions other market participants would use in pricing the asset or liability based on the best information available in the circumstances. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability, and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. The hierarchy is broken down into three levels based on the observability of inputs as follows:

  

No transfers between fair value hierarchy levels occurred during the three months ended March 31, 2016 .

Assets and Liabilities Measured at Fair Value on a Recurring Basis

Energen classifies the fair value of multiple derivative instruments executed under master netting arrangements as net derivative assets and liabilities. The following fair value hierarchy tables present information about Energen’s assets and liabilities measured at fair value on a recurring basis:

Derivative Instruments: The fair value of Energen’s derivative commodity instruments is determined using market transactions and other market evidence whenever possible, including market-based inputs to models and broker or dealer quotations. Our OTC derivative contracts trade in less liquid markets with limited pricing information as compared to markets with actively traded, unadjusted quoted prices; accordingly, the determination of fair value is inherently more difficult. OTC derivatives for which we are able to substantiate fair value through directly observable market prices are classified within Level 2 of the fair value hierarchy. These Level 2 fair values consist of swaps priced in reference to NYMEX oil and natural gas prices. OTC derivatives valued using unobservable market prices have been classified within Level 3 of the fair value hierarchy. These Level 3 fair values include basin specific, basis and natural gas liquids swaps. We consider the frequency of pricing and variability in pricing between sources in determining whether a market is considered active. While Energen does not have access to the specific assumptions used in its counterparties’ valuation models, Energen maintains communications with its counterparties and discusses pricing practices. Further, we corroborate the fair value of our transactions by comparison of market-based price sources.

Energen utilizes a discounted cash flow model in valuing its interest rate derivatives, which are comprised of interest rate swap agreements. The fair value attributable to Energen's interest rate derivative contracts is based on (i) the contracted notional amounts, (ii) active market-quoted London Interbank Offered Rate (LIBOR) yield curves and (iii) the applicable credit-adjusted risk-free rate yield curve.

At March 31, 2016, Energen had interest rate swap agreements with a notional value of $50.0 million . The interest rate swaps exchange a variable interest rate for a fixed interest rate of 1.0425 percent. The fair value of our interest rate swaps was a $0.1 million and a $0.2 million liability at March 31, 2016 and December 31, 2015 , respectively, and is classified as Level 2 fair value liabilities. The fair value of our interest rate swaps are recognized on a gross basis in accounts payable on the balance sheets.

Level 3 Fair Value Instruments: Energen prepared a sensitivity analysis to evaluate the hypothetical effect that changes in the prices used to estimate fair value would have on the fair value of its Level 3 instruments. We estimate that a 10 percent increase or decrease in commodity prices would result in an approximate $0.8 million change in the fair value of open Level 3 derivative contracts and to the results of operations.

The table below sets forth a summary of changes in the fair value of Energen’s Level 3 derivative commodity instruments as follows:

*Includes $2.2 million in mark-to-market gains and $10.3 million in mark-to-market losses for the three months ended March 31, 2016 and 2015, respectively.

The table below sets forth quantitative information about Energen’s Level 3 fair value measurements of derivative commodity instruments as follows:

*Discounted cash flow represents an income approach in calculating fair value including the referenced unobservable input and a discount reflecting credit quality of the counterparty.

Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis

Certain assets and liabilities are reported at fair value on a nonrecurring basis in Energen’s consolidated balance sheets. The following methods and assumptions were used to estimate the fair values.

Asset retirement obligations: Energen’s asset retirement obligations (ARO) primarily relate to the future plugging, abandonment and reclamation of wells and facilities. We recognize a liability for the fair value of the ARO in the periods incurred. See Note 11, Asset Retirement Obligations, for further discussion related to these ARO’s. These assumptions are classified as Level 3 fair value.

Asset Impairments: We monitor our oil and natural gas properties as well as the market and business environments in which we operate and make assessments about events that could result in potential impairment. Such potential events may include, but are not limited to, commodity price declines, unanticipated increased operating costs, and lower than expected field production performance. If a material event occurs, Energen makes an estimate of undiscounted future cash flows to determine whether the asset is impaired. If the asset is impaired, we will record an impairment loss for the difference between the net book value of the properties and the fair value of the properties. The fair value of the properties typically is estimated using discounted cash flows and values derived from purchase and sale agreements and similar support as applicable. Cash flow and fair value estimates require Energen to make projections and assumptions for pricing, demand, competition, operating costs, legal and regulatory issues, discount rates and other factors for many years into the future.

These assumptions are classified as Level 3 fair value. See Note 13, Asset Impairment, for impairments recognized by Energen during the three months ended March 31, 2016 and 2015.

Financial Instruments not Carried at Fair Value

The stated value of cash and cash equivalents, short-term investments, accounts receivable (net of allowance), and short-term debt approximates fair value due to the short maturity of the instruments. The Company invested in certain short-term investments that qualify and were classified as cash and cash equivalents. Energen had allowance for doubtful accounts of $0.7 million at both March 31, 2016 and December 31, 2015, respectively. The fair value of Energen’s long-term debt, including the current portion, was approximately $481.2 million and $690.1 million and had a carrying value of $554.0 million and $776.5 million at March 31, 2016

and December 31, 2015 , respectively. The fair values are based on market prices of similar debt issues having the same remaining maturities, redemption terms and credit rating. Short-term debt is classified as Level 1 fair value and long-term debt is classified as Level 2 fair value.

The aggregate maturities of Energen’s long-term debt outstanding at March 31, 2016 are as follows:

The debt agreements of Energen contain financial and nonfinancial covenants including routine matters such as timely payment of principal and interest, maintenance of corporate existence and restrictions on liens. Although none of the agreements have events of default based on credit ratings, the interest rates applicable to the syndicated credit facility discussed below may adjust based on credit rating changes during certain periods.

Under Energen’s Indenture dated September 1, 1996 with The Bank of New York as Trustee, a cross default provision provides that any debt default of more than $10 million by Energen or Energen Resources will constitute an event of default by Energen. The Indenture does not include a restriction on the payment of dividends.

Credit Facility: On September 2, 2014, Energen entered into a five -year syndicated secured credit facility with domestic and foreign lenders. On April 13, 2016, the borrowing base and aggregate commitments were reduced to $1.05 billion in association with the semi-annual redetermination required under the agreement. Energen’s obligations under the syndicated credit facility are unconditionally guaranteed by Energen Resources. Subject to release of collateral in certain periods upon the achievement of certain investment grade ratings from designated ratings agencies, the credit facility is collateralized by certain assets of Energen, including a pledge of equity interests in subsidiaries of Energen other than Energen Resources, and by mortgages on substantially all of Energen Resources’ oil and natural gas properties. The current credit facility qualifies for classification as long-term debt on the consolidated balance sheets. The financial covenants of the credit facility require Energen to maintain a ratio of total debt to consolidated income before interest expense, income taxes, depreciation, depletion, amortization, exploration expense and other non-cash income and expenses (EBITDAX) less than or equal to 4.0 to 1.0; to maintain a ratio of consolidated current assets (adjusted to include amounts available for borrowings and exclude non-cash derivative instruments) to consolidated current liabilities (adjusted to exclude maturities under the credit facility and non-cash derivative instruments) greater than or equal to 1.0 to 1.0; and, during certain periods, to maintain a ratio of the net present value of proved reserves of our oil and natural gas properties to consolidated total debt greater

than or equal to 1.50 to 1.0. We are also bound by covenants which limit our ability to incur additional indebtedness, make certain distributions or alter our corporate structure. Energen may not pay dividends during an event of default if the payment would result in an event of default or if availability is less than 10 percent of the loan limit under the credit facility. Our credit facility also limits our ability to enter into commodity hedges based on projected production volumes. In addition, the terms of our credit facility limit the amount we can borrow to a borrowing base amount which is determined by our lenders in their sole discretion based on their valuation of our proved reserves and their internal criteria including commodity price outlook. The borrowing base amount is subject to redetermination semi-annually and for event-driven unscheduled redeterminations. Our next scheduled redetermination is October 1, 2016.

Under the credit facility, a cross default provision provides that any debt default of more than $75 million by Energen or Energen Resources will constitute an event of default by Energen.

Upon an uncured event of default under the credit facility, all amounts owing under the credit facility, if any, depending on the nature of the event of default will automatically, or may upon notice by the administrative agent or the requisite lenders thereunder, become immediately due and payable and the lenders may terminate their commitments under the defaulted facility. Energen was in compliance with the terms of its credit facility as of March 31, 2016 .

The following is a summary of information relating to Energen’s credit facility:

*Effective April 13, 2016, borrowing commitments were lowered to $1.05 billion .

   

Energen’s interest expense was $9.8 million and $11.8 million for the three months ended March 31, 2016 and 2015, respectively. Energen’s total interest expense for the three months ended March 31, 2016 and 2015 included debt issuance costs related to long-term debt, including our credit facility, of $0.8 million and $0.8 million , respectively. Energen had no capitalized interest for the three months ended March 31, 2016. Capitalized interest for the three months ended March 31, 2015 was not significant. At March 31, 2016, Energen paid commitment fees on the unused portion of the available credit facility at a current annual rate of 30 basis points.

In periods of loss, shares that otherwise would have been included in diluted average common shares outstanding are excluded. The Company had 233,547 and 284,150 of excluded shares for the three months ended March 31, 2016 and 2015, respectively.

Energen had the following shares that were excluded from the computation of diluted EPS, as inclusion would be anti-dilutive:

6. EQUITY OFFERING

During the first quarter of 2016, Energen issued 18,170,000 additional shares of common stock through a public equity offering. We received net proceeds of approximately $381.1 million , after deducting offering expenses. Net proceeds from this offering were used to repay borrowings under our credit facility and for general corporate purposes.

During the second quarter of 2015, Energen issued 5,700,000 additional shares of common stock through a public equity offering. We received net proceeds of approximately $398.6 million , after deducting offering expenses. Net proceeds from this offering were used to repay borrowings under our credit facility and for general corporate purposes.

7. STOCK COMPENSATION

Stock Incentive Plan

Stock Options: The Stock Incentive Plan provides for the grant of incentive stock options and non-qualified stock options to officers and key employees. Options granted under the Stock Incentive Plan provide for the purchase of Energen common stock at not less than the fair market value on the date the option was granted. The sale or transfer of the shares is limited during certain periods. All outstanding options vest within three years from date of grant and expire 10 years from the grant date.

Restricted Stock: Additionally, the Stock Incentive Plan provides for the grant of restricted stock and restricted stock units. In March 2016, Energen awarded 154,633 restricted stock units with a grant-date fair value of $26.77 . These awards have a three year vesting period and were valued based on the quoted market price of Energen’s common stock at the date of grant.

Performance Share Awards: The Stock Incentive Plan also provides for the grant of performance share awards to eligible employees based on predetermined Company performance criteria at the end of an award period. The Stock Incentive Plan provides that payment of earned performance share awards be made in the form of Energen common stock. Performance share awards are valued using the Monte Carlo model which uses historical volatility and other variables to estimate the probability of satisfying the market condition of the award. Energen granted 136,191 performance share awards during the first quarter of 2016 with a three year vesting period and a grant-date fair value of $22.74 .

Stock Repurchase Program

During the three months ended March 31, 2016 and 2015, Energen had non-cash purchases of approximately $2.4 million and $4.4 million , respectively, of Energen common stock in conjunction with tax withholdings on our non-qualified deferred compensation plan and other stock compensation. Energen utilized internally generated cash flows in payment of the related tax withholdings.

Energen’s non-qualified supplemental retirement plans were terminated effective December 31, 2014. Distributions under the plans were partially made in the first quarter of 2015 with the remainder of approximately $14.5 million paid in the first quarter of 2016. The Company expects to make no additional benefit payments with respect to the termination of the non-qualified supplemental retirement plans. In the first quarter of 2016 and 2015, Energen incurred a settlement charge of $3.3 million and $2.5 million , respectively, for the payment of lump sums from the non-qualified supplemental retirement plans. Also in the first quarter of 2015, Energen incurred settlement charges of $0.2 million for the payment of lump sums from the qualified defined benefit pension plans.

The components of net periodic postretirement benefit expense for Energen’s postretirement benefit plan were as follows:

There are no required contributions to the postretirement benefit plan during 2016. In the three months ended March 31, 2016, Energen incurred a curtailment gain of $0.8 million in connection with the reduction in workforce.

9. COMMITMENTS AND CONTINGENCIES    

Commitments and Agreements: Under various agreements for third-party gathering, treatment, transportation or other services, Energen is committed to deliver minimum production volumes or to pay certain costs in the event the minimum quantities are not delivered. These delivery commitments are approximately 5.3 million barrels of oil equivalent (MMBOE) through October 2020 .

Legal Matters: Energen and its affiliates are, from time to time, parties to various pending or threatened legal proceedings and we have accrued a provision for our estimated liability. Certain of these lawsuits include claims for punitive damages in addition to other specified relief. We recognize a liability for contingencies, including an estimate of legal costs to be incurred, when information available indicates both a loss is probable and the amount of the loss can be reasonably estimated. Based upon information presently

available, and in light of available legal and other defenses, contingent liabilities arising from threatened and pending litigation are not considered material in relation to the respective financial positions of Energen and its affiliates. It should be noted, however, that there is uncertainty in the valuation of pending claims and prediction of litigation results.

On November 4, 2015, Energen Resources filed a quiet title action against Endeavor Energy Resources. L.P. in the District Court of Howard County, Texas, to remove a cloud on the title to approximately 10,000 acres leased by Energen Resources in that county. Energen Resources believes the cloud on title arises from a prior, unreleased but partially terminated oil and gas lease covering the leased lands. Endeavor filed a counterclaim alleging Energen Resources tortiously interfered with a prospective contract seeking

$300 million in damages. On April 28, 2016, the trial judge ruled with respect to the acreage not held by production that Endeavor’s lease terminated prior to the date Energen Resources entered into its lease and additionally ruled that Endeavor’s claim for tortuous interference will be dismissed with prejudice.

Environmental Matters: Various environmental laws and regulations apply to the operations of Energen and Energen Resources. Historically, the cost of environmental compliance has not materially affected our financial position, results of operations or cash flows. New regulations, enforcement policies, claims for damages or other events could result in significant unanticipated costs.

During January 2014, Energen Resources responded to a General Notice and Information Request from the Environmental Protection Agency regarding the Reef Environmental Site in Sylacauga, Talladega County, Alabama. The letter identifies Energen Resources as a potentially responsible party under The Comprehensive Environmental Response, Compensation, and Liability Act for the cleanup of the Site. In 2008, Energen hired a third party to transport approximately 3,000 gallons of non-hazardous wastewater to Reef Environmental for wastewater treatment. Reef Environmental ceased operating its wastewater treatment system in 2010. Due to its one time use of Reef Environmental for a small volume of non-hazardous wastewater, Energen Resources has not accrued a liability for cleanup of the Site.

New Mexico Audits: In 2011, Energen Resources received an Order to Perform Restructured Accounting and Pay Additional Royalties (the Order), following an audit performed by the Taxation and Revenue Department (the Department) of the State of New Mexico on behalf of the Office of Natural Resources Revenue (ONRR), of federal oil and gas leases in New Mexico. The audit covered periods from January 2004 through December 2008 and included a review of the computation and payment of royalties due on minerals removed from specified U.S. federal leases. The Order addressed ONRR’s efforts to change accounting and reporting practices, and to unbundle fees charged by third parties that gather, compress and transport natural gas production. ONRR now maintains that all or some of such fees are not deductible.

Energen Resources appealed the Order in 2011 and in July 2012, on a motion from ONRR, the Order was remanded. In August 2014, ONRR issued its Revised Order and Energen Resources appealed the Revised Order. In the Revised Order, ONRR ordered that Energen pay additional royalties on production from certain federal leases in the amount of $129,700 . At ONRR’s request the Revised Order was also remanded in August 2015. On April 15, 2016 ONRR issued its Second Revised Order. The Second Revised Order directs Energen Resources to pay additional royalties of $189,000 , replacing the previous demand of $129,700 . Energen had previously estimated that application of the ONRR position to all of the Company’s federal leases would result in ONRR claims up to approximately $24 million , plus interest and penalties from 2004 forward. ONRR began implementing its unbundling initiative in 2010, but seeks to implement its revisions retroactively, despite the fact that they conflict with previous audits, allowances and industry practice. Energen plans to appeal and vigorously contest the Second Revised Order, the predecessor orders and the findings. Management is unable, at this time, to determine a range of reasonably possible losses, and no amount has been accrued as of March 31, 2016 .

10. EXPLORATORY COSTS

Energen capitalizes exploratory drilling costs until a determination is made that the well or project has either found proved reserves or is impaired. After an exploratory well has been drilled and found oil and natural gas reserves, a determination may be pending as to whether the oil and natural gas quantities can be classified as proved. In those circumstances, Energen continues to capitalize the drilling costs pending the determination of proved status if (i) the well has found a sufficient quantity of reserves to justify its completion as a producing well and (ii) Energen is making sufficient progress assessing the reserves and the economic and operating viability of the project. Capitalized exploratory drilling costs are presented in proved properties in the balance sheets. If the exploratory well is determined to be a dry hole, the costs are charged to exploration expense. Other exploration costs, including geological and geophysical costs, are expensed as incurred.

The following table sets forth capitalized exploratory well costs and includes additions pending determination of proved reserves, reclassifications to proved reserves and costs charged to expense:

The following table sets forth capitalized exploratory well costs:

At March 31, 2016 , Energen had 33 gross exploratory wells either drilling or waiting on results from completion and testing in the Permian Basin. As of March 31, 2016, the Company had one gross well capitalized greater than a year. This well is scheduled for completion during 2017. No wells were capitalized for a period greater than one year as of December 31, 2015.

11. ASSET RETIREMENT OBLIGATIONS

Energen’s asset retirement obligations (ARO) primarily relate to the future plugging, abandonment and reclamation of wells and facilities. We recognize a liability for the fair value of the ARO in the periods incurred. The ARO fair value liability is determined by calculating the present value of the estimated future cash outflows we expect to incur to plug, abandon and reclaim our producing properties at the end of their productive lives, and is recognized on a discounted basis incorporating an estimate of performance risk specific to Energen. Subsequent to initial measurement, liabilities are accreted to their present value and capitalized costs are depreciated over the estimated useful lives of the related assets. Upon settlement of the liability, Energen may recognize a gain or loss for differences between estimated and actual settlement costs.

The following table reflects the components of the change in Energen’s ARO balance:

*Adjustment to the reclassification of the asset retirement obligation associated with certain properties included as liabilities related to assets held for sale in current liabilities on the balance sheet at March 31, 2016.

The following table provides details of the reclassifications out of accumulated other comprehensive income (loss).