Exhibit 99.1

WGL Holdings, Inc. Reports First Quarter Fiscal Year 2012 Financial Results;

Affirms Fiscal Year 2012 Non-GAAP Guidance

Consolidated Results

WGL Holdings, Inc. (NYSE: WGL), the parent company of Washington Gas Light Company (Washington Gas) and other energy-related subsidiaries, today reported net income determined in accordance with generally accepted accounting principles in the United States of America (GAAP) for the quarter ended December 31, 2011 of $50.4 million, or $0.98 per share, compared to net income of $65.2 million, or $1.28 per share, reported for the quarter ended December 31, 2010.

Financial performance is also evaluated based on non-GAAP operating earnings (loss). Non-GAAP operating earnings (loss) excludes the effects of: (i) unrealized mark-to-market gains (losses) on energy-related derivatives in our regulated utility and retail energy marketing segments; (ii) certain gains and losses associated with optimizing the utility segment’s system capacity assets and (iii) certain unusual transactions. In addition, non-GAAP operating earnings for our wholesale energy solutions segment reflect an adjustment to GAAP earnings to reflect storage inventory valued at current market prices. Refer to “Use of Non-GAAP Operating Earnings (Loss)” and supporting reconciliations attached to this news release for a detailed discussion of management’s use of this non-GAAP financial measure, as well as reconciliations of net income determined in accordance with GAAP to non-GAAP operating earnings (loss) for both our consolidated and segment results.

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For the quarter ended December 31, 2011, non-GAAP operating earnings were $58.1 million, or $1.13 per share, compared to non-GAAP operating earnings of $52.6 million, or $1.03 per share, for the same quarter of the prior fiscal year.

This quarter, we have made certain changes to our operating segments to reflect the recent growth of our non-utility business activities and the impact of those activities on our financial performance. All of our commercial energy assets and operating activities are now reported within a newly-defined operating segment entitled commercial energy systems. All activities of Washington Gas Energy Systems, Inc. (WGESystems) are included in the commercial energy systems segment. WGESystems had previously been reported in the design build energy systems segment, which is now being eliminated as an operating segment. In addition, we have transferred all commercial solar projects, previously reported under retail energy-marketing into the commercial energy systems segment. In the future, commercial solar projects, energy efficiency projects and combined heat and power projects, which we own and manage directly, will be reported as commercial energy systems. We have also established wholesale energy solutions as a new segment that contains the activities of Capitol Energy Ventures Corp. (CEV), our non-utility asset optimization business, which we began in fiscal year 2010 and previously included in our segment reporting as part of “other activities.” Prior period operating segment information has been restated to reflect these new classifications.

“We are pleased to announce strong first quarter earnings that reflect our ongoing success in executing our strategies,” said Terry D. McCallister, Chairman and Chief Executive Officer of WGL Holdings. “Our non-GAAP results improved compared to the prior year as we began to realize higher revenues from our recent rate cases as well as continued gains in our non-utility businesses. Based on these results and our optimism for the year ahead, we are affirming our non-GAAP guidance midpoint of $2.52 per share for 2012.”

First Quarter Results by Business Segment

Regulated Utility Segment

For the quarter ended December 31, 2011, the regulated utility segment reported net income of $44.4 million, or $0.86 per share, an increase of $3.7 million or $0.06 per share, over net income of $40.7 million, or $0.80 per share, reported for the first quarter of the prior fiscal year. After adjustments, non-GAAP operating income for the regulated utility segment was $44.1 million, or $0.86 per share, for the quarter ended December 31, 2011, virtually unchanged from non-GAAP operating earnings of $44.3 million, or $0.87 per share, for the same quarter of the prior fiscal year. Higher revenues from the implementation of new rates in Virginia and Maryland and an increase of more than 9,300 average active customer meters were offset by: (i) lower realized margins associated with our asset optimization program; (ii) higher operation and maintenance expenses and (iii) higher depreciation expense due to the growth in, and changes in the asset mix of, our investment in utility.

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Retail Energy-Marketing Segment

For the quarter ended December 31, 2011, the retail energy-marketing segment reported net income of $0.8 million, or $0.02 per share, compared to net income of $24.9 million, or $0.49 per share, reported for the same quarter of the prior fiscal year. Non-GAAP operating earnings for the retail energy-marketing segment were $13.1 million, or $0.25 per share, for the quarter ended December 31, 2011, an increase of $6.3 million, or $0.12 per share, over non-GAAP operating earnings of $6.8 million, or $0.13 per share, for the same quarter of the prior fiscal year. The differences between GAAP net income and non-GAAP operating earnings are due to adjustments to eliminate unrealized mark-to-market gains and losses attributable to certain wholesale energy supply and retail sales contracts. The increase in non-GAAP operating earnings reflects higher realized natural gas and electricity margins. The increase in natural gas sales margins for the quarter is primarily attributed to favorable spreads between retail prices and storage withdrawals and a more favorable pattern of margin recognition in the current quarter versus the same quarter of the prior year. These favorable impacts are partially offset by lower retail sales volumes resulting from warmer weather and less profitable portfolio optimization activity. Electric sales margins were higher due to favorable price conditions and a more favorable pattern of margin recognition in the current quarter versus the same quarter of the prior year. The pattern of margin recognition varies from year to year.

Commercial Energy Systems

For the quarter ended December 31, 2011, the commercial energy systems segment reported net income of $0.3 million compared to a net loss of $(2,000) for the same quarter last year. The increase in earnings is primarily due to the commencement of project work for government agency customers that was delayed in the prior year. There were no non-GAAP adjustments for this segment for any of the periods presented.

Wholesale Energy Solutions

For the quarter ended December 31, 2011, the wholesale energy solutions segment reported net income of $5.2 million, or $0.10 per share, an increase of $5.1 million, over net income of $0.1 million for the same period of the prior fiscal year. Non-GAAP operating earnings for the wholesale energy solutions segment were $1.0 million, or $0.02 per share, compared to $1.9 million, or $0.04 per share, for the same period of the prior fiscal year. Non-GAAP operating earnings for the year were lower than in the prior year principally due to lower market prices of natural gas supply as well as higher operation and maintenance expense as a result of new storage and optimization arrangements. Partially offsetting this decrease in operating earnings were higher recognized margins associated with our optimization strategies.

Earnings Outlook

We are raising our GAAP earnings estimate for the fiscal year 2012 to a range of $2.64 per share to $2.76 per share. This estimate includes projected fiscal year 2012 earnings from our regulated utility segment in a range of $1.84 per share to $1.90 per share and projected fiscal year 2012 earnings from our unregulated business segments in a range of $0.80 per share to $0.86 per share.

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We are affirming our consolidated earnings estimate for fiscal year 2012 based on non-GAAP operating earnings to a range of $2.46 per share to $2.58 per share. This estimate includes projected fiscal year 2012 non-GAAP operating earnings from our regulated utility segment in a range of $1.82 per share to $1.88 per share, and projected fiscal year 2012 non-GAAP operating earnings from our unregulated business segments in a range of $0.64 per share to $0.70 per share. Refer to the “Reconciliation of GAAP Earnings Guidance to Non-GAAP Earnings Guidance” attached to this press release for a reconciliation of our GAAP earnings per share estimate to our estimate based on non-GAAP operating earnings per share.

We assume no obligation to update this guidance. The absence of any statement by us in the future should not be presumed to represent an affirmation of this earnings guidance. For the assumptions underlying this guidance, please refer to the slides accompanying our webcast that will be posted to the WGL Holdings website, www.wglholdings.com.

Other Information

We will hold a conference call at 10:30 a.m. Eastern Time on February 6, 2012, to discuss our first quarter fiscal year 2012 financial results. The live conference call will be available to the public via a link located on the WGL Holdings website, www.wglholdings.com. To hear the live webcast, click on the “Webcast” link located on the home page of the referenced site. The webcast and related slides will be archived on the WGL Holdings website through March 6, 2012.

Headquartered in Washington, D.C., WGL Holdings, Inc. has four operating segments: (i) the regulated utility segment which primarily consists of Washington Gas, a natural gas utility that serves over one million customers throughout metropolitan Washington, D.C., and the surrounding region; (ii) the retail-energy marketing segment which consists of Washington Gas Energy Services, Inc., a third-party marketer that competitively sells natural gas and electricity; (iii) the commercial energy systems segment which consists of Washington Gas Energy Systems, Inc., a provider of design-build energy efficiency solutions to government and commercial clients and commercial solar projects and (iv) the wholesale energy solutions segment which consists of Capitol Energy Ventures Corp., an asset optimization business that acquires, manages and optimizes natural gas storage and transportation assets. Additional information about WGL Holdings, Inc. is available on our website, www.wglholdings.com.

Unless otherwise noted, earnings per share amounts are presented on a diluted basis, and are based on weighted average common and common equivalent shares outstanding.

Please see the attached comparative statements for additional information on our operating results. Also attached to this news release are reconciliations of net income determined in accordance with GAAP to non-GAAP operating earnings (loss) for both our consolidated and segment results as well as reconciliations of our GAAP earnings guidance to our non-GAAP earnings guidance.

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Forward-Looking Statements

This news release and other statements by us include forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 with respect to the outlook for earnings, revenues and other future financial business performance or strategies and expectations. Forward-looking statements are typically identified by words such as, but not limited to, “estimates,” “expects,” “anticipates,” “intends,” “believes,” “plans,” and similar expressions, or future or conditional verbs such as “will,” “should,” “would,” and “could.” Although we believe such forward-looking statements are based on reasonable assumptions, we cannot give assurance that every objective will be achieved. Forward-looking statements speak only as of today, and we assume no duty to update them. Factors that could cause actual results to differ materially from those expressed or implied include, but are not limited to, general economic conditions and the factors discussed under the “Risk Factors” heading in our most recent annual report on Form 10-K and other documents we have filed with, or furnished to, the U.S. Securities and Exchange Commission.

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WGL Holdings, Inc.

Consolidated Balance Sheets

(Unaudited)

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WGL Holdings, Inc.

Consolidated Statements of Income

(Unaudited)

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WGL Holdings, Inc.

Consolidated Financial and Operating Statistics

(Unaudited)

FINANCIAL STATISTICS

UTILITY GAS STATISTICS

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WGL HOLDINGS, INC.

USE OF NON-GAAP OPERATING EARNINGS (LOSS)

(Unaudited)

The attached reconciliations are provided to clearly identify adjustments made to net income calculated in accordance with GAAP to derive non-GAAP operating earnings (loss). Management believes non-GAAP operating earnings (loss) provides a more meaningful representation of our earnings from ongoing operations by adjusting for the effects of: (i) unrealized mark-to-market gains and losses from energy-related derivatives for our regulated utility and retail marketing operations; (ii) certain gains and losses associated with optimizing the utility segment’s capacity assets; (iii) changes in the measured value of our inventory for our wholesale energy solutions segment and (iv) certain unusual transactions. This presentation facilitates analysis by providing a consistent and comparable measure to help management, investors and analysts better understand and evaluate our operating results and performance trends, and assist in analyzing period-to-period comparisons. Additionally, we use this non-GAAP measure to report to the board of directors and to evaluate management’s performance. The economic substance underlying our adjustments to calculate non-GAAP operating earnings (loss) is as follows:

We also exclude valuation adjustments to the carrying value of non-system natural gas storage inventory in our regulated utility segment. This inventory is held solely to support asset optimization transactions. Valuation adjustments to reflect lower-of-cost or market under current accounting standards may not be representative of the margins that will be realized and shared with our utility ratepayers. Non-GAAP earnings reflect actual margins realized based on the unadjusted historical cost in storage when inventory is withdrawn and sold.

There are limits in using non-GAAP operating earnings (loss) to analyze our results, as they are not prepared in accordance with GAAP and may be different from non-GAAP financial measures used by other companies. In addition, using non-GAAP operating earnings (loss) per share to analyze our earnings may have limited value as it excludes certain items that may have a material impact on our reported financial results. We compensate for these limitations by providing investors with the attached reconciliations to net income, the most directly comparable GAAP financial measure.

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WGL HOLDINGS, INC. (Consolidating by Segment)

RECONCILIATION OF GAAP NET INCOME (LOSS) TO

NON-GAAP OPERATING EARNINGS (LOSS)

(Unaudited)

(Footnote references are described on the following page.)

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WGL HOLDINGS, INC. (Consolidated by Quarter)

RECONCILIATION OF GAAP NET INCOME (LOSS) TO

NON-GAAP OPERATING EARNINGS (LOSS)

(Unaudited)

Footnotes:

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WGL HOLDINGS, INC.

RECONCILIATION OF GAAP EARNINGS GUIDANCE TO

NON-GAAP EARNINGS GUIDANCE

FISCAL YEAR ENDING SEPTEMBER 30, 2012

Footnotes:

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